Non-terrestrial network-terrestrial network interworking

Abstract

A wireless transmit / receive unit (WTRU) may camp on a non-terrestrial network (NTN) cell and evaluate one or more terrestrial network (TN) cells to determine, for example, whether to change a radio access network (RAN)-based notification area (RNA). In an example, the WTRU may receive an indication to change from a first TN cell to an NTN cell. The WTRU may perform cell reselection to the NTN cell based on the indication. The first TN may be associated with the first RNA. The WTRU may evaluate a second TN cell associated with a second RNA. The WTRU may determine that cell reselection conditions associated with the second TN cell are satisfied. The WTRU may perform cell reselection to the second TN cell based on the determination that the cell reselection conditions are satisfied.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 395,387, filed August 5, 2022, the disclosure of which is incorporated herein by reference in its entirety. [Background technology]

[0002] Mobile communications using wireless communications continue to evolve. The fifth generation of mobile communications radio access technology (RAT) may be referred to as 5G new radio (NR). A previous (traditional) generation of mobile communications RAT may be, for example, fourth-generation (4G) long-term evolution (LTE). Wireless communication devices may establish communications with other devices and data networks via an access network, such as, for example, a radio access network (RAN). Summary of the Invention

[0003] SUMMARY Disclosed herein are systems, methods, and means for non-terrestrial network (NTN)-terrestrial network (TN) interworking.

[0004] A wireless transmit-receive unit (WTRU) may camp on an NTN cell and evaluate one or more TN cells to determine, for example, whether to change a Radio Access Network (RAN)-based notification area (RNA). In an example, the WTRU may receive an indication to change from a first TN cell to an NTN cell. The WTRU may perform cell reselection to the NTN cell based on the indication. The first TN cell may be associated with the first RNA. The WTRU may evaluate a second TN cell associated with the second RNA. The WTRU may determine that a cell reselection condition associated with the second TN cell is satisfied. The WTRU may perform cell reselection to the second TN cell based on the determination that the cell reselection condition is satisfied. For example, evaluating the second TN cell associated with the second RNA may include measuring the second TN cell associated with the second RNA and / or determining that a cell reselection condition associated with the second TN cell is satisfied.

[0005] The WTRU may evaluate the second TN cell, for example, during a time period associated with the WTRU being configured to monitor paging messages from the NTN cell in the RRC_INACTIVE state. In an example, the WTRU may receive an indication to change the WTRU's state from the RRC_CONNECTED state to the RRC_INACTIVE state. The WTRU may initiate a change from the RRC_CONNECTED state to the RRC_INACTIVE state based on the indication. The WTRU may monitor for paging messages from the NTN cell in the RRC_INACTIVE state (e.g., during a time period associated with the WTRU being configured to operate in the RRC_INACTIVE state). The WTRU may evaluate the second TN cell when the WTRU monitors for paging messages from the NTN cell. If a cell reselection condition associated with the second TN cell is satisfied, the WTRU may perform cell reselection to the second TN cell associated with the second RNA. The WTRU may receive a paging message from the NTN cell in the RRC_INACTIVE state. The WTRU may initiate a change of its state from the RRC_INACTIVE state to the RRC_CONNECTED state based on receipt of the paging message. The WTRU may receive a data transmission from a second TN cell associated with a second RNA while in the RRC_CONNECTED state (e.g., during a time period associated with the WTRU being configured to operate in the RRC_CONNECTED state).

[0006] In an example, the WTRU may send an indication of a change from a first RNA to a second RNA to the NTN cell. The WTRU may receive an indication from the NTN cell to change the WTRU's state from an RRC_INACTIVE state to an RRC_IDLE state. Based on the indication, the WTRU may initiate a change from the RRC_INACTIVE state to an RRC_IDLE state, for example, before cell reselection to the second TN cell is performed.

[0007] The WTRU may evaluate one or more TN cells, for example, based on identification information associated with the one or more TN cells. The WTRU may receive identification information associated with the one or more TN cells, where the one or more TN cells may include a first TN cell associated with a first RNA and / or a second TN cell associated with a second RNA. The WTRU may evaluate one or more TN cells for cell reselection based on the identification information. The WTRU may evaluate one or more TN cells during a time period associated with the WTRU being configured to monitor paging messages from the NTN cell. In an example, the WTRU may limit its evaluation to one or more TN cells (e.g., without evaluating the NTN cell for cell reselection).

[0008] The WTRU may determine satisfaction of a cell reselection condition associated with the second TN cell based on a reference signal received power (RSRP) associated with the second TN cell. The WTRU may receive a cell reselection threshold in a radio resource control (RRC) message. The WTRU may determine an RSRP associated with the second TN cell associated with the second RNA. To determine satisfaction of a cell reselection condition associated with the second TN cell, the WTRU may determine that the RSRP associated with the second TN cell is greater than or equal to the cell reselection threshold.

[0009] The WTRU may determine satisfaction of a cell reselection condition associated with the second TN cell based on a cell reselection priority associated with the second TN cell. The WTRU may receive cell reselection priority information in an RRC message. The WTRU may determine a cell reselection priority associated with the second TN cell associated with the second RNA. The WTRU may determine satisfaction of a cell reselection condition associated with the second TN cell based on the cell reselection priority associated with the second TN cell and the cell reselection priority information received in the RRC message. [Brief explanation of the drawings]

[0010] [Figure 1A] FIG. 1 is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented. [Figure 1B] 1B is a system diagram illustrating an exemplary wireless transmit / receive unit (WTRU) that may be used within the communication system illustrated in FIG. 1A, according to one embodiment. [Figure 1C] 1B is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communication system illustrated in FIG. 1A, according to one embodiment. [Figure 1D] 1B is a system diagram illustrating a further exemplary RAN and a further exemplary CN that may be used within the communication system illustrated in FIG. 1A, according to one embodiment. [Figure 2] 1 is an example of a depiction of different interfaces in a non-terrestrial network. [Figure 3] 1 is an example of a WTRU triggered transition from RRC_IDLE to RRC_CONNECTED. [Figure 4] 10 is an example of a WTRU triggered transition from RRC_IDLE rejection. [Figure 5] 10 is an example of a WTRU triggered transition from RRC_INACTIVE to RRC_CONNECTED (WTRU context retrieval successful). [Figure 6] 10 is an example of a WTRU triggered transition from RRC_INACTIVE to RRC_CONNECTED (WTRU context retrieval failed). [Figure 7] 1 is an example of a denial from the network when the WTRU attempts to resume a connection. [Figure 8] 1 is an example of a network-triggered transition from RRC_INACTIVE to RRC_CONNECTED. [Figure 9] 10 is an example of an RNA update procedure with WTRU context rearrangement. [Figure 10]10 is an example of a cyclic RNA update procedure without WTRU context rearrangement. [Figure 11] 10 is an example of an RNA update procedure involving a transition to RRC_IDLE. [Figure 12] 10 is an example of a resume request responded to with a release with redirection, with WTRU context relocation. [Figure 13] 1 is an exemplary procedure for CN-controlled subgrouping. [Figure 14] 10 is an exemplary procedure for WTRU ID-based subgrouping. [Figure 15] This is an example of the NTN-TN network layer. [Figure 16] This is an example of releasing to RRC_IDLE to camp on NTN. [Figure 17] 1 is an example of RNA alterations based on TN measurements. [Figure 18] 1 is an example of RNA alterations based on TN measurements. [Figure 19] 19 is an example 1900 for evaluation of one or more TN cells to determine RNA renewal. DETAILED DESCRIPTION OF THE INVENTION

[0011] 1A is a diagram illustrating an example communication system 100 in which one or more disclosed embodiments may be implemented. Communication system 100 may be a multiple-access system that provides content, such as voice, data, video, messaging, broadcasts, etc., to multiple wireless users. Communication system 100 may enable multiple wireless users to access such content through sharing of system resources, including wireless bandwidth. For example, the communication system 100 may employ one or more channel access methods such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tail unique-word DFT-Spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multicarrier (FBMC), etc.

[0012] 1A, communications system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RANs 104 / 113, CNs 106 / 115, public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, although it will be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a "station" and / or "STA," may be configured to transmit and / or receive wireless signals and may include user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a mobile phone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone, a medical device and application (e.g., for remote surgery), an industrial device and application (e.g., a robot and / or other wireless device operating in an industrial and / or automated processing chain context), a consumer electronics device, a device operating on a commercial wireless network and / or an industrial wireless network, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be referred to interchangeably as a UE.

[0013] The communications system 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communications networks, such as the CN 106 / 115, the Internet 110, and / or other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node B, an Encoder B, a Home Node B, a Home eNodeB, a gNB, an NR Node B, a site controller, an access point (AP), a wireless router, etc. Although the base stations 114a, 114b are each depicted as a single element, it will be understood that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0014] The base station 114a may be part of the RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, etc. The base station 114a and / or base station 114b may be configured to transmit and / or receive radio signals on one or more carrier frequencies, which may be referred to as a cell (not shown). These frequencies may be licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide wireless service coverage for a particular geographic area, which may be relatively fixed or may change over time. A cell may be further divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In one embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and may utilize multiple transceivers per sector of the cell, for example, using beamforming to transmit and / or receive signals in desired spatial directions.

[0015] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0016] More specifically, as noted above, the communications system 100 may be a multiple-access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base station 114a and the WTRUs 102a, 102b, 102c in the RAN 104 / 113 may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 115 / 116 / 117 using wideband CDMA (WCDMA). WCDMA may include communications protocols such as High-Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High-Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High-Speed ​​Uplink Packet Access (HSUPA).

[0017] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro).

[0018] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may establish the air interface 116 using New Radio (NR).

[0019] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may jointly implement LTE radio access and NR radio access, e.g., using the principle of dual connectivity (DC). Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions sent to and from multiple types of base stations (e.g., eNBs and gNBs).

[0020] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement a wireless technology such as IEEE 802.11 (i.e., Wireless Fidelity, WiFi), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access, WiMAX), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), or the like.

[0021] 1A may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point and may utilize any suitable RAT to facilitate wireless connectivity in a local area such as a business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a road, etc. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a picocell or a femtocell. As shown in FIG. 1A, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not need to access the Internet 110 through the CN 106 / 115.

[0022] The RAN 104 / 113 may communicate with the CN 106 / 115, which may be any type of network configured to provide voice, data, application, and / or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have various quality of service (QoS) requirements, such as different throughput, latency, error tolerance, reliability, data throughput, and mobility requirements. The CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, and / or perform high-level security functions such as user authentication. Although not shown in FIG. 1A , it will be understood that the RAN 104 / 113 and / or the CN 106 / 115 may communicate directly or indirectly with other RANs employing the same RAT as the RAN 104 / 113 or a different RAT. For example, the CN 106 / 115, in addition to being connected to the RAN 104 / 113, which may utilize NR radio technology, may also communicate with another RAN (not shown) employing GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0023] The CN 106 / 115 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network providing plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices, which use common communication protocols such as the transmission control protocol (TCP), the user datagram protocol (UDP), and / or the internet protocol (IP) of the TCP / IP Internet protocol suite. The network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the network 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 / 113 or a different RAT.

[0024] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links.) For example, the WTRU 102c shown in FIG. 1A may be configured to communicate with a base station 114a, which may employ a cellular-based wireless technology, and a base station 114b, which may employ an IEEE 802.2 wireless technology.

[0025] 1B is a system diagram illustrating an example WTRU 102. As shown in FIG. 1B, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be understood that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0026] The processor 118 may be a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. While FIG. 1B depicts the processor 118 and the transceiver 120 as separate components, it will be understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0027] The transmit / receive element 122 may be configured to transmit or receive signals to or from a base station (e.g., base station 114a) over the air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In an embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive, for example, IR signals, UV signals, or visible light signals. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF signals and light signals. It will be understood that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0028] 1B as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0029] The transceiver 120 may be configured to modulate signals transmitted by the transmit / receive element 122 and demodulate signals received by the transmit / receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as, for example, NR and IEEE 802.11.

[0030] The processor 118 of the WTRU 102 may be coupled to and may receive user-entered data from a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light-emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. Additionally, the processor 118 may access information from and store data in any type of suitable memory, such as non-removable memory 130 and / or removable memory 132. The non-removable memory 130 may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, etc. In other embodiments, the processor 118 may access information from and store data in memory that is not physically located on the WTRU 102, such as on a server or home computer (not shown).

[0031] The processor 118 may receive power from the power source 134 and may be configured to distribute and / or control the power to other components within the WTRU 102. The power source 134 may be any suitable device for providing power to the WTRU 102. For example, the power source 134 may include one or more dry batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0032] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to, or instead of, information from the GPS chipset 136, the WTRU 102 may receive location information from base stations (e.g., base stations 114a, 114b) over the air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by way of any suitable location-determination method while remaining consistent with an embodiment.

[0033] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or videos), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, etc. The peripheral device 138 may include one or more sensors, which may be one or more of a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, a direction sensor, a proximity sensor, a temperature sensor, a time sensor, a geolocation sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0034] The WTRU 102 may include a full-duplex radio where transmission and reception of some or all of the signals associated with a particular subframe (e.g., for both the UL (e.g., for transmission) and downlink (e.g., for reception)) may be parallel and / or simultaneous. The full-duplex radio may include an interference management unit to reduce and or substantially eliminate self-interference through either hardware (e.g., a choke) or signal processing via a processor (e.g., via a separate processor (not shown) or processor 118). In one embodiment, the WTRU 102 may include a half-duplex radio for transmission and reception of either some or all of the signals (e.g., associated with a particular subframe for either the UL (e.g., for transmission) or downlink (e.g., for reception)).

[0035] 1C is a system diagram illustrating the RAN 104 and the CN 106, according to one embodiment. As noted above, the RAN 104 may employ E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also communicate with the CN 106.

[0036] The RAN 104 may include eNodeBs 160a, 160b, and 160c, although it will be understood that the RAN 104 may include any number of eNodeBs while remaining consistent with an embodiment. The eNodeBs 160a, 160b, and 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 116. In one embodiment, the eNodeBs 160a, 160b, and 160c may implement MIMO technology. Thus, the eNodeB 160a may, for example, use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0037] Each of the eNodeBs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, etc. As shown in FIG. 1C, the eNodeBs 160a, 160b, 160c may communicate with one another via an X2 interface.

[0038] 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. Although each of the foregoing elements is depicted as part of the CN 106, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0039] The MME 162 may be connected to each of the eNodeBs 160a, 160b, 160c in the RAN 104 via an S1 interface and may function as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, activating / deactivating bearers, selecting a particular serving gateway during initial attach of the WTRUs 102a, 102b, 102c, etc. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies such as GSM and / or WCDMA.

[0040] The SGW 164 may be connected to each of the eNodeBs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to and from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions such as anchoring the user plane during inter-eNodeB handovers, triggering paging when DL data is available to the WTRUs 102a, 102b, 102c, and managing and storing the context of the WTRUs 102a, 102b, 102c.

[0041] The SGW 164 may be connected to a PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0042] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional landline communications devices. For example, the CN 106 may include or communicate with an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. Additionally, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0043] Although the WTRU is illustrated in FIGS. 1A-1D as a wireless terminal, it is contemplated that in certain representative embodiments, such a terminal may use a wired communication interface (e.g., temporarily or permanently) with the communication network.

[0044] In a representative embodiment, the other network 112 may be a WLAN.

[0045] A WLAN in infrastructure Basic Service Set (BSS) mode may have an access point (AP) of the BSS and one or more stations (STAs) associated with the AP. The AP may have access to or interface with a Distribution System (DS) or another type of wired / wireless network that carries traffic into and / or out of the BSS. Traffic originating from outside the BSS to a STA may arrive through the AP and be delivered to the STA. Traffic originating from a STA to a destination outside the BSS may be sent to the AP for delivery to the respective destination. Traffic between STAs within a BSS may be sent, for example, through the AP, where a source STA may send traffic to the AP, and the AP may deliver the traffic to the destination STA. Traffic between STAs within a BSS may be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic may be sent between (e.g., directly between) a source STA and a destination STA using a direct link setup (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and STAs within or using the IBSS (e.g., all of the STAs) may communicate directly with each other. The IBSS mode of communication may be referred to herein as an "ad hoc" communication mode.

[0046] When using the 802.11ac infrastructure mode of operation or a similar mode of operation, an AP may transmit beacons on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., a 20 MHz wide bandwidth) or a width that is dynamically configured via signaling. The primary channel may be the operating channel of the BSS and may be used by STAs to establish a connection with the AP. In certain representative embodiments, for example, in an 802.11 system, Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) may be implemented. With CSMA / CA, STAs (e.g., all STAs), including the AP, may sense the primary channel. If a particular STA senses / detects and / or determines that the primary channel is busy, the particular STA may back off. One STA (e.g., only one station) may transmit in a given BSS at any given time.

[0047] High Throughput (HT) STAs may use 40 MHz wide channels for communication, which may be formed, for example, through a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels.

[0048] A Very High Throughput (VHT) STA may support 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz wide channels. A 40 MHz and / or 80 MHz channel may be formed by combining contiguous 20 MHz channels. A 160 MHz channel may be formed by combining eight contiguous 20 MHz channels or by combining two non-contiguous 80 MHz channels, which may be referred to as an 80+80 configuration. For the 80+80 configuration, after channel encoding, the data may pass through a segment parser that may separate the data into two streams. Inverse Fast Fourier Transform (IFFT) processing and time-domain processing may be performed separately on each stream. The streams may be mapped to two 80 MHz channels, and the data may be transmitted by the transmitting STA. At the receiver of the receiving STA, the operations described above for the 80+80 configuration may be reversed, and the combined data may be sent to Medium Access Control (MAC).

[0049] Sub-1 GHz operating modes are supported by 802.11af and 802.11ah. Channel operating bandwidths and carriers are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, while 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to representative embodiments, 802.11ah may support meter-type control / machine-type communications, such as MTC devices, within a macro coverage area. MTC devices may have limited capabilities, including, for example, support for (e.g., only support for) certain specific and / or limited bandwidths. MTC devices may include batteries with above-threshold battery life (e.g., to maintain very long battery life).

[0050] WLAN systems that can support multiple channels and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include a channel that can be designated as a primary channel. The primary channel can have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel can be configured and / or limited by the STAs among all STAs operating in the BSS that support the minimum bandwidth operating mode. In an 802.11ah embodiment, the primary channel can be 1 MHz wide for STAs (e.g., MTC-type devices) that support (e.g., only) the 1 MHz mode, even if the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or Network Allocation Vector (NAV) configuration can depend on the status of the primary channel. For example, if the primary channel is busy due to a STA (that only supports 1 MHz operating mode) transmitting to the AP, the entire available frequency band may be considered busy, even though most of the frequency band may remain idle and be available for use.

[0051] In the United States, the available frequency band that can be used by 802.11ah is 902MHz to 928MHz. In South Korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 916.5MHz to 927.5MHz. The total bandwidth available for 802.11ah is 6MHz to 26MHz, depending on country regulations.

[0052] 1D is a system diagram illustrating the RAN 113 and the CN 115, according to one embodiment. As mentioned above, the RAN 113 may employ NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also communicate with the CN 115.

[0053] The RAN 113 may include gNBs 180a, 180b, and 180c, although it will be understood that the RAN 113 may include any number of gNBs while remaining consistent with the embodiments. The gNBs 180a, 180b, and 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, and 180c may implement MIMO technology. For example, the gNBs 180a and 180b may utilize beamforming to transmit signals to and / or receive signals from the gNBs 180a, 180b, and 180c. Thus, the gNB 180a may transmit wireless signals to and / or receive wireless signals from the WTRU 102a using, for example, multiple antennas. In one embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum, while the remaining component carriers may be on licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement Coordinated Multi-Point (CoMP) technology. For example, the WTRU 102a may receive coordinated transmissions from the gNBs 180a and 180b (and / or 180c).

[0054] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with scalable numerology. For example, the OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or transmission time intervals (TTIs) of different or scalable lengths (e.g., including different numbers of OFDM symbols and / or lasting different lengths of absolute time).

[0055] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c without accessing another RAN (e.g., eNodeBs 160a, 160b, 160c, etc.). In a standalone configuration, the WTRUs 102a, 102b, 102c may utilize one or more of the gNBs 180a, 180b, 180c as mobility anchor points. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in unlicensed spectrum. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate / connect with a gNB 180a, 180b, 180c while also communicating / connecting with another RAN, such as an eNodeB 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement a DC principle to communicate with one or more gNBs 180a, 180b, 180c and one or more eNodeBs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the eNodeBs 160a, 160b, 160c may act as mobility anchors for the WTRUs 102a, 102b, 102c, and the gNBs 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0056] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, support for network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data to User Plane Functions (UPFs) 184a, 184b, routing of control plane information to Access and Mobility Management Functions (AMFs) 182a, 182b, etc. As shown in FIG. 1D , the gNBs 180a, 180b, 180c may communicate with each other via an Xn interface.

[0057] 1D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. While each of the foregoing elements is depicted as part of the CN 115, it will be understood that any of these elements may be owned and / or operated by an organization other than the operator of the CN.

[0058] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N2 interface and may function as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, supporting network slicing (e.g., handling different PDU sessions with different requirements), selecting a particular SMF 183a, 183b, managing registration areas, terminating NAS signaling, mobility management, etc. The network slicing may be used by the AMF 182a, 182b to customize the CN support of the WTRUs 102a, 102b, 102c based on the type of service utilizing the WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases, such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services for machine type communication (MTC) access, etc. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies, such as WiFi.

[0059] The SMFs 183a and 183b may be connected to the AMFs 182a and 182b in the CN 115 via an N11 interface. The SMFs 183a and 183b may also be connected to the UPFs 184a and 184b in the CN 115 via an N4 interface. The SMFs 183a and 183b may select and control the UPFs 184a and 184b and configure the routing of traffic through the UPFs 184a and 184b. The SMFs 183a and 183b may perform other functions such as managing and assigning IP addresses for UEs, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notification, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0060] The UPFs 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks such as the Internet 110 to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPFs 184, 184b may perform other functions such as routing and forwarding packets, enforcing user plane policy, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, etc.

[0061] The CN 115 may facilitate communication with other networks. For example, the CN 115 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 115 and the PSTN 108. Additionally, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to local data networks (DNs) 185a, 185b through the UPFs 184a, 184b via an N3 interface to the UPFs 184a, 184b and an N6 interface between the UPFs 184a, 184b and the DNs 185a, 185b.

[0062] 1A-1D and their corresponding descriptions, one or more or all of the functions described herein with respect to one or more of the WTRUs 102a-d, base stations 114a and 114b, eNodeBs 160a-c, MME 162, SGW 164, PGW 166, gNBs 180a-c, AMFs 182a and 182b, UPFs 184a and 184b, SMFs 183a and 183b, DNs 185a and 185b, and / or any other devices described herein may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more or all of the functions described herein. For example, the emulation devices may be used to test other devices and / or simulate network and / or WTRU functions.

[0063] The emulation devices may be designed to implement one or more tests of other devices in a lab environment and / or a carrier network environment. For example, one or more emulation devices may perform one or more or all functions while fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices in the communication network. One or more emulation devices may perform one or more or all functions while temporarily implemented / deployed as part of a wired and / or wireless communication network. The emulation devices may be directly coupled to another device for testing purposes and / or may perform testing using wireless communication over the air.

[0064] One or more emulation devices may perform one or more functions, inclusive, while not being implemented / deployed as part of a wired and / or wireless communication network. For example, the emulation devices may be utilized in test scenarios in a test lab and / or in an undeployed (e.g., test) wired and / or wireless communication network to implement testing of one or more components. One or more emulation devices may be test equipment. Direct RF coupling and / or wireless communication via RF circuitry (which may include, e.g., one or more antennas) may be used by the emulation devices to transmit and / or receive data.

[0065] A WTRU on a TN (e.g., a WTRU in RRC_INACTIVE or RRC_CONNECTED state) may send an indication of preference to camp on a non-terrestrial network (NTN), for example, to the TN. The TN may release the WTRU to RRC_IDLE state. The WTRU may perform cell reselection to camp on the NTN and / or monitor paging from the NTN.

[0066] For example, the WTRU may transmit an indication of NTN availability, e.g., in a message. The WTRU may receive an RRC release message from the TN. The WTRU may transition from an RRC inactive operating condition to an RRC idle operating condition based on the RRC release message received from the TN. The WTRU may camp on the NTN and attempt to decode a paging message from the NTN. The message including the indication of NTN availability may include WTRU assistance information (e.g., UE assistance information) and / or an RRC release request.

[0067] The WTRU may camp on the NTN in RRC_INACTIVE state and monitor RNA changes on the TN, e.g., using neighbor cell measurements and / or cell reselection evaluation. The WTRU may perform a RAN notification area update if a TN RNA change is detected, e.g., via the current NTN or by triggering cell reselection to the TN.

[0068] For example, the WTRU may operate in an RRC inactive operating condition. The WTRU may, for example, camp on an NTN while operating in an RRC inactive operating condition. The WTRU may detect a change in an RNA associated with the TN and perform an RNA update based on the detected change in the RNA associated with the TN. The WTRU may detect a change in the RNA associated with the TN based on cell selection criteria. While camped on the NTN, the WTRU may measure multiple TN cells neighboring the TN cell associated with the RNA. The WTRU may determine that cell reselection criteria are met based on measurements of the multiple TN cells and may detect a change in the RNA associated with the TN based on the determination that the cell selection criteria are met. The WTRU may perform an RNA update via the NTN network or by triggering cell reselection to the TN.

[0069] Disclosed herein are systems, methods, and means for NTN-TN interworking. A WTRU may camp on an NTN cell and evaluate one or more TN cells to determine, for example, whether to change its RNA. In an example, the WTRU may camp on an NTN cell and evaluate one or more TN cells to determine, for example, whether to change its RNA. In an example, the WTRU may receive an indication to change from a first TN cell to an NTN cell. The WTRU may perform cell reselection to the NTN cell based on the indication. The first TN may be associated with a first RNA. The WTRU may evaluate a second TN cell associated with a second RNA. The WTRU may determine that a cell reselection condition associated with the second TN cell is satisfied. The WTRU may perform cell reselection to the second TN cell based on the determination that the cell reselection condition is satisfied. For example, evaluating the second TN cell associated with the second RNA may include measuring the second TN cell associated with the second RNA and / or determining that a cell reselection condition associated with the second TN cell is satisfied.

[0070] The WTRU may evaluate the second TN cell, for example, during a time period associated with the WTRU being configured to monitor paging messages from the NTN cell in the RRC_INACTIVE state. In an example, the WTRU may receive an indication to change the WTRU's state from the RRC_CONNECTED state to the RRC_INACTIVE state. The WTRU may initiate a change from the RRC_CONNECTED state to the RRC_INACTIVE state based on the indication. The WTRU may monitor for paging messages from the NTN cell in the RRC_INACTIVE state (e.g., during a time period associated with the WTRU being configured to operate in the RRC_INACTIVE state). The WTRU may evaluate the second TN cell when the WTRU monitors for paging messages from the NTN cell. If a cell reselection condition associated with the second TN cell is satisfied, the WTRU may perform cell reselection to the second TN cell associated with the second RNA. The WTRU may receive a paging message from the NTN cell in the RRC_INACTIVE state. The WTRU may initiate a change of its state from the RRC_INACTIVE state to the RRC_CONNECTED state based on receipt of the paging message. The WTRU may receive a data transmission from a second TN cell associated with a second RNA while in the RRC_CONNECTED state (e.g., during a time period associated with the WTRU being configured to operate in the RRC_CONNECTED state).

[0071] In an example, the WTRU may send an indication of a change from a first RNA to a second RNA to the NTN cell. The WTRU may receive an indication from the NTN cell to change the WTRU's state from an RRC_INACTIVE state to an RRC_IDLE state. Based on the indication, the WTRU may initiate a change from the RRC_INACTIVE state to an RRC_IDLE state, for example, before cell reselection to the second TN cell is performed.

[0072] The WTRU may evaluate one or more TN cells, for example, based on identification information associated with the one or more TN cells. The WTRU may receive identification information associated with the one or more TN cells, where the one or more TN cells may include a first TN cell associated with a first RNA and / or a second TN cell associated with a second RNA. The WTRU may evaluate one or more TN cells for cell reselection based on the identification information. The WTRU may evaluate one or more TN cells during a time period associated with the WTRU being configured to monitor paging messages from the NTN cell. In an example, the WTRU may limit its evaluation to one or more TN cells (e.g., without evaluating the NTN cell for cell reselection).

[0073] The WTRU may determine satisfaction of a cell reselection condition associated with the second TN cell based on a reference signal received power (RSRP) associated with the second TN cell. The WTRU may receive a cell reselection threshold in a radio resource control (RRC) message. The WTRU may determine an RSRP associated with the second TN cell associated with the second RNA. To determine satisfaction of a cell reselection condition associated with the second TN cell, the WTRU may determine that the RSRP associated with the second TN cell is greater than or equal to the cell reselection threshold.

[0074] The WTRU may determine satisfaction of a cell reselection condition associated with the second TN cell based on a cell reselection priority associated with the second TN cell. The WTRU may receive cell reselection priority information in an RRC message. The WTRU may determine a cell reselection priority associated with the second TN cell associated with the second RNA. The WTRU may determine satisfaction of a cell reselection condition associated with the second TN cell based on the cell reselection priority associated with the second TN cell and the cell reselection priority information received in the RRC message.

[0075] The NTN may be implemented in one or more examples herein.

[0076] NTNs may facilitate the deployment of wireless networks in areas where ground-based antennas may be impractical, for example, due to geography and / or cost. Combined with terrestrial networks, NTNs could enable ubiquitous coverage of 5G networks. NTN deployments could support basic speech and / or text anywhere in the world and, when combined with the proliferation of next-generation low-earth orbit satellites, enable enhanced services (e.g., web browsing).

[0077] The NTN may include a platform (e.g., an airborne or space platform) that transmits signals from ground-based base stations (e.g., gNBs) to WTRUs and vice versa via a gateway (GW). The NTN may support power class 3 WTRUs with omnidirectional antennas and linear polarization, and / or very small aperture antenna (VSAT) terminals with directional antennas and circular polarization. Support for narrow-band Internet of Things (NB-IoT) and enhanced MTC (eMTC) type devices may be provided. Regardless of device type, it may be envisioned that one or more (e.g., all) NTN WTRUs may be global navigation satellite system (GNSS) capable.

[0078] Platforms (e.g., airborne or space platforms) may be classified with respect to orbit, focusing, for example, on low-earth orbit (LEO) satellites with an altitude range of 300-1500 km and geostationary earth orbit (GEO) satellites with an altitude of 35,786 km. Other platform classifications (e.g., medium-earth orbit (MEO) satellites with an altitude range of 7,000-25,000 km and high-altitude platform stations (HAPS) with altitudes of 8-50 km) may be assumed to be implicitly supported. Satellite platforms may be further classified as having "transparent" or "regenerative" payloads. Transparent satellite payloads may implement frequency conversion and RF amplification in the uplink and downlink, for example, with multiple transparent satellites potentially connected to one ground-based gNB. Regenerative satellite payloads may implement a full gNB or a gNB distributed unit (DU) onboard the satellite. The recovery payload may perform digital processing on the signal, including, for example, one or more of the following: demodulation; decoding; re-encoding; re-modulation; filtering. References herein to a gNB may refer to an exemplary base station, and the gNB may be replaced with any other suitable base station.

[0079] The following radio interfaces may be defined in the NTN: a feeder link (e.g., a radio link between a GW and a satellite), a service link (e.g., a radio link between a satellite and a WTRU), and an inter-satellite link (ISL) (e.g., a transmission link between satellites). The ISL may be supported by (e.g., only by) a regenerative payload and may be a 3GPP radio or proprietary optical interface. Figure 2 is an example depicting different interfaces in a non-terrestrial network. A WTRU in one or more examples (e.g., examples shown in one or more figures herein) may be interchangeably referred to as a UE.

[0080] Depending on the satellite payload configuration, different interfaces (e.g., different 3GPP interfaces) may be used for (e.g., each) radio link. For transparent payloads, the NR-Uu radio interface may be used for the service link and / or the feeder link. For regenerative payloads, the NR-Uu interface may be used for the service link and the satellite radio interface (SRI) may be used for the feeder link. A user plane (UP) / control plane (CP) protocol stack for (e.g., each) payload configuration may be used.

[0081] An NTN satellite may support multiple cells, each of which may include one or more satellite beams. The one or more satellite beams may cover a footprint on Earth (e.g., in the manner in which terrestrial cells cover a footprint on Earth), which may range from 100 km to 1000 km in diameter in LEO deployments and from 200 to 3500 km in diameter in GEO deployments. The beam footprint in a GEO deployment may remain fixed relative to the Earth, whereas in a LEO deployment, the area covered by the beam / cell may change over time due to, for example, satellite movement. Beam movement may be classified as "Earth-moving," in which the LEO beam moves continuously across the Earth, or as "Earth-fixed," in which the beam may be steered to continue covering a fixed location until a different cell (e.g., a new cell) overtakes the coverage area (e.g., in discrete and coordinated changes).

[0082] Due to the altitude and / or beam diameter of the NTN platform, the round-trip time (RTT) and maximum differential delay associated with the NTN may be larger (e.g., significantly larger) than those of terrestrial systems. In a transparent NTN deployment, the RTT may range from 25.77 ms (e.g., for LEO at 600 km altitude) to 541.46 ms (e.g., for GEO), and the maximum differential delay may range from 3.12 ms to 10.3 ms. The RTT of the regenerated payload may, in some examples, be approximately half the RTT of the transparent payload because the transparent configuration may include a service link and a feeder link, whereas the RTT of the regenerated payload may consider the service link (e.g., only the service link). To minimize the impact on some NR systems (e.g., to avoid preamble ambiguity or to properly adjust the timing of the receive window), the WTRU may perform timing pre-compensation before initial access.

[0083] The pre-compensation procedure may require the WTRU to obtain one or more of the following: its position (e.g., via GNSS); feeder link delay and / or common delay (e.g., via satellite ephemeris data); satellite position (e.g., via satellite ephemeris data). The satellite ephemeris data may be broadcast (e.g., periodically) in the system information and may include one or more of the following: satellite speed; direction; velocity. The WTRU may estimate the distance and / or delay from the satellite and / or add a feeder link delay component to obtain the full WTRU-gNB RTT (e.g., UE-gNB RTT), which may be used to offset one or more of the following: timers; receive windows; or timing relationships. It may be assumed that frequency compensation may be performed, for example, by the network.

[0084] WTRU mobility and / or measurement reporting may be provided in NTNs. In NTNs, RSRP differences between cell centers and cell edges may not be as significant as in terrestrial systems. This, combined with the relatively larger areas of cell overlap, may in some instances result in reduced reliability of some measurement-based mobility (e.g., traditional measurement-based mobility) in NTN environments. Different conditional handover and measurement reporting triggers associated with location and / or time (e.g., different triggers dependent on location and / or time) may be provided. Enhanced mobility may be used in some instances (e.g., LEO deployments) where, due to satellite movement, stationary WTRUs may be expected to perform mobility periodically (e.g., approximately every 7 seconds depending on deployment characteristics).

[0085] Mobility, state transitions, and paging may be described herein. Mobility in RRC_IDLE may be described herein. Cell selection may be described herein.

[0086] The principle of public land mobile network (PLMN) selection in NR may be based on the PLMN selection principle. Cell selection may be required at transitions from RM-DEREGISTERED to RM-REGISTERED, from CM-IDLE to CM-CONNECTED, and from CM-CONNECTED to CM-IDLE, and may be based on one or more of the following principles: The WTRU Non-Access-Stratum (NAS) layer may identify the selected PLMN and equivalent PLMNs. Cell selection may be based on a cell-defining synchronization signal block (CD-SSB) located on the synchronization raster (see Section 5.2.4) (e.g., the WTRU may search the NR frequency band and, for (e.g., each) carrier frequency, identify the strongest cell according to the CD-SSB). The WTRU may then read the broadcasted cell system information to identify the PLMN (e.g., the WTRU may search each (e.g.,) carrier in turn ("initial cell selection") or may use stored information to shorten the search ("stored information cell selection")); the WTRU may attempt to identify a suitable cell (if unable to identify a suitable cell, it may attempt to identify an acceptable cell).When a suitable cell can be found, or if an acceptable cell (e.g., only acceptable cells are found), it may camp on that cell and initiate a cell reselection procedure (e.g., a suitable cell may be one whose measured cell attributes satisfy the cell selection criteria; the cell PLMN may be the selected PLMN, the registered PLMN, or an equivalent PLMN; the cell may be one that is not excluded or reserved, i.e., the cell may be one that is not part of a tracking area that is in the list of "forbidden tracking areas for roaming"; an acceptable cell may be one whose measured cell attributes satisfy the cell selection criteria and the cell is not excluded); the IAB-MT may apply the cell selection procedure as described for the WTRU, with the following differences (e.g., the IAB-MT may ignore any cell exclusion or cell reservation indicators included in the cell system information broadcast; if the cell system information broadcast indicates IAB support for the selected PLMN or the selected SNPN, the IAB-MT may consider (e.g., only consider) the cell as a candidate for cell selection).

[0087] The WTRU may transition to RRC_IDLE. Upon transitioning from RRC_CONNECTED or RRC_INACTIVE to RRC_IDLE, the WTRU may camp on a cell as a result of cell selection according to frequency (e.g., allocated by RRC in a state transition message, if any).

[0088] The WTRU may recover from out-of-coverage. The WTRU may attempt to find a suitable cell using stored information or methods described herein for initial cell selection. In some examples, if no suitable cell is found on any frequency or RAT, the WTRU may attempt to find an acceptable cell.

[0089] In multi-beam operation, cell quality may be derived between beams corresponding to the same cell.

[0090] Cell reselection may be described herein. A WTRU in RRC_IDLE may perform resource reselection. The principle of the procedure may be one or more of the following: cell reselection may be based on CD-SSB located on the synchronization raster; the WTRU may perform measurements of attributes of the serving cell and neighboring cells to enable the reselection process (e.g., carrier frequency (e.g., only carrier frequency) may be indicated for inter-frequency neighboring cell search and measurements); cell reselection may identify cells on which the WTRU may camp. It may be based on cell reselection criteria involving measurements of the serving cell and neighboring cells (e.g., intra-frequency reselection may be based on cell ranking; inter-frequency reselection may be based on absolute priority where the WTRU attempts to camp on the highest priority frequency available; a neighbor cell list (NCL) may be provided by the serving cell to handle specific cases for intra-frequency and inter-frequency neighboring cells; an exclusion list may be provided to prevent the WTRU from reselecting specific intra-frequency and inter-frequency neighboring cells; an allowed list may be provided to request the WTRU to reselect specific intra-frequency and inter-frequency neighboring cells (e.g., only specific intra-frequency and inter-frequency neighboring cells); cell reselection may be speed dependent; service-specific prioritization; slice-specific cell reselection information may be provided to facilitate the WTRU reselecting cells that support a specific slice). In multi-beam operation, cell quality may be derived between beams corresponding to the same cell.

[0091] The WTRU may perform a state transition. Figure 3 is an example of a WTRU-triggered transition from RRC_IDLE to RRC_CONNECTED. Figure 3 illustrates a WTRU-triggered transition from RRC_IDLE to RRC_CONNECTED (e.g., a NAS portion may also be provided). At 1, the WTRU may request to set up a different connection (e.g., a new connection) than RRC_IDLE. At 2 / 2a, the gNB may complete the RRC setup procedure. A scenario in which the gNB rejects the request may be described herein. At 3, the first NAS message from the WTRU may be sent to the AMF, piggybacked on an RRCSetupComplete. At 4 / 4a / 5 / 5a, additional NAS messages may be exchanged between the WTRU and the AMF. At 6, the AMF may prepare WTRU context data (including protocol data unit (PDU) session context, security keys, WTRU radio capabilities, WTRU security capabilities, etc.) and send it to the gNB. In 7 / 7a, the gNB may activate AS security with the WTRU. In 8 / 8a, the gNB may perform a reconfiguration to set up a signaling radio bearer (SRB) 2 and a data radio bearer (DRB) for the WTRU, or an SRB 2 and optionally a DRB for Integrated Access and Backhaul (IAB)-Mobile Termination (MT). In 9, the gNB may notify the AMF that the setup procedure may be completed. The RRC messages in 1 and 2 may use SRB 0, and some or all subsequent messages may use SRB 1. The messages in 7 / 7a may be integrity protected. From 8, some or all messages may be integrity protected and encrypted. In the case of a signaling-only connection, 8 may be skipped since SRB 2 and DRB may not be set up.

[0092] Figure 4 is an example of a WTRU triggered transition rejection from RRC_IDLE. Figure 4 illustrates a rejection from the network when the WTRU attempts to set up a connection from RRC_IDLE. At 1, the WTRU may attempt to set up a different connection (e.g., a new connection) from RRC_IDLE. At 2, the gNB may not be able to process the procedure, for example, due to congestion. At 3, the gNB may send an RRC Reject (with a waiting time) to keep the WTRU in RRC_IDLE.

[0093] Mobility in RRC_INACTIVE may be described herein.

[0094] RRC_INACTIVE may be a state in which the WTRU remains CM-CONNECTED and may move within an area configured by next generate (NG)-RAN without notifying the NG-RAN. In RRC_INACTIVE, the last serving gNB node may retain the WTRU context and WTRU-associated NG connection with the serving AMF and UPF.

[0095] While the WTRU may be RRC_INACTIVE, if the last serving gNB may receive DL data from the UPF or DL ​​WTRU-related signaling from the AMF (excluding the WTRU context release command message, e.g., UE context release as defined in 3GPP), it may page in the cell corresponding to the RNA, and if the RNA includes the cells of a neighboring gNB, it may send Xn Application Protocol (XnAP) RAN paging to the neighboring gNB.

[0096] Upon receiving a WTRU Context Release Command message while the WTRU may be RRC_INACTIVE, the last serving gNB may page in the cell corresponding to the RNA and may send an XnAP RAN paging to the neighboring gNB if the RNA includes the cell of the neighboring gNB to explicitly release the WTRU.

[0097] Upon receiving an NG RESET message while the WTRU may be RRC_INACTIVE, the last serving gNB may page the involved WTRU in the cell corresponding to the RNA and may send an XnAP RAN paging to the neighboring gNB if the RNA includes the cell of the neighboring gNB to explicitly release the involved WTRU.

[0098] Upon RAN paging failure, the gNB may behave accordingly.

[0099] The AMF may provide core network assistance information to the NG-RAN node to assist the NG-RAN node in determining whether a WTRU can be sent in RRC_INACTIVE and to support WTRU configuration and paging in RRC_INACTIVE. The core network assistance information may include a registration area configured for the WTRU, a periodic registration update timer, and a WTRU identification index value, as well as WTRU-specific discontinuous reception (DRX), an indication of when the WTRU can be configured in Mobile Initiated Connection Only (MICO) mode by the AMF, expected WTRU behavior, WTRU radio capabilities for paging, a paging early indication (PEI) with paging subgrouping assistance information, and NR paging eDRX information and a paging cause indicator for voice services. The WTRU registration area may be taken into account by the NG-RAN node when configuring the RRC. The WTRU-specific DRX and WTRU identification index values ​​may be used by the NG-RAN node for RAN paging. The periodic registration update timer may be taken into account by the NG-RAN node to configure the periodic RNA update timer. The NG-RAN node may take into account expected WTRU behavior to assist in WTRU RRC state transition decisions. The NG-RAN node may use the WTRU radio capabilities for paging during RAN paging. The NG-RAN node may take into account the PEI with paging subgrouping assistance information for subgroup paging in RRC_INACTIVE. The PEI with paging subgrouping assistance information may be included when sending XnAP RAN paging to neighboring NG-RAN nodes. The NG-RAN node may take NR paging eDRX information into account to configure RAN paging when the NR WTRU may be RRC_INACTIVE. NR paging eDRX information for RRC_IDLE and RRC_INACTIVE may be included when sending XnAP RAN paging to neighboring NG-RAN nodes.The NG-RAN node may take into account the paging cause indicator for voice services to include the paging cause in RAN pages for WTRUs in RRC_INACTIVE state. The paging cause may be included when sending XnAP RAN pages to neighboring NG-RAN nodes.

[0100] Upon transition to RRC_INACTIVE, the NG-RAN node may configure the WTRU with a periodic RNA update timer value. If the periodic RNA update timer expires without notification from the WTRU, the gNB may behave accordingly.

[0101] If the WTRU accesses a gNB other than the last serving gNB, the receiving gNB may trigger an XnAP UE Context Retrieval procedure to obtain the WTRU context from the last serving gNB, and may also trigger an Xn-U Address Index procedure that includes tunnel information for potential recovery of data from the last serving gNB. If the WTRU context retrieval is successful, the receiving gNB may perform slice-aware admission control if it receives slice information, may become the serving gNB, and may further trigger an NGAP path switch request and applicable RRC procedures. After the path switch procedure, the serving gNB may trigger the release of the WTRU context at the last serving gNB via an XnAP WTRU Context Release procedure.

[0102] If the WTRU may not be reachable to the last serving gNB, the gNB may fail (e.g., any) AMF-initiated WTRU-related Class 1 procedure that allows signaling of the unsuccessful operation in the respective response message, which may trigger a NAS non-delivery indication procedure to report non-delivery of any non-PDU session-related NAS PDUs received from the AMF.

[0103] If the WTRU accesses a gNB other than the last serving gNB and the receiving gNB does not find a valid WTRU context, the receiving gNB may, for example, perform the establishment of a different RRC connection (e.g., a new RRC connection) instead of resuming the previous RRC connection. WTRU context retrieval may also fail, and thus a different RRC connection (e.g., a new RRC connection) may be established if the serving AMF has changed.

[0104] A WTRU in RRC_INACTIVE state may be requested to initiate an RNA update procedure when moving from the configured RNA. Upon receiving an RNA update request from the WTRU, the receiving gNB may trigger an XnAP WTRU context retrieval procedure to obtain the WTRU context from the last serving gNB and may decide to send the WTRU back to RRC_INACTIVE state, move the WTRU to RRC_CONNECTED state, or send the WTRU to RRC_IDLE. In the case of periodic RNA updates, if the last serving gNB decides not to relocate the WTRU context, it may fail the WTRU context retrieval procedure and send the WTRU back to RRC_INACTIVE or RRC_IDLE directly via an encapsulated RRC release message.

[0105] Cell reselection may be performed. A WTRU in RRC_INACTIVE may perform resource reselection. The principle of the procedure may be similar to that in the RRC_IDLE state.

[0106] A RAN-based notification area may be used. A WTRU in RRC_INACTIVE state may be configured by the last serving NG-RAN node with an RNA, where the RNA may cover a single cell or multiple cells and may be included within the CN registration area; an Xn connection may be available within the RNA; a RAN-based notification area update (RNAU) may be sent periodically by the WTRU and may be sent when the WTRU's cell reselection procedure selects a cell that does not belong to the configured RNA.

[0107] There may be several alternatives for how the RNA may be configured: a list of cells (e.g., the WTRU may be provided with an explicit list of one or more cells that make up the RNA); a list of RAN areas (e.g., the WTRU may be provided with one or more RAN Area IDs, where the RAN Area may be a subset of the CN Tracking Area or may be equal to the CN Tracking Area; a RAN Area may be specified by one RAN Area ID, where the RAN Area ID may include the TAC and optionally the RAN Area Code; a cell may broadcast one or more RAN Area IDs in the system information).

[0108] The NG-RAN may provide different RNA definitions to different WTRUs (e.g., the NG-RAN may not simultaneously mix different definitions for the same WTRU). A WTRU may support some or all of the RNA configuration options listed above.

[0109] A state transition may occur: A WTRU triggered transition from RRC_INACTIVE to RRC_CONNECTED may occur.

[0110] Figure 5 is an example of a WTRU-triggered transition from RRC_INACTIVE to RRC_CONNECTED (WTRU context retrieval successful). Figure 5 illustrates a WTRU-triggered transition from RRC_INACTIVE to RRC_CONNECTED when WTRU context retrieval is successful. At 1, the WTRU may resume from RRC_INACTIVE if it has been assigned an inactive radio network temporary identifier (I-RNTI) by the last serving gNB. At 2, the gNB may request the last serving gNB to provide the WTRU context data if it can resolve the gNB identity contained in the I-RNTI. At 3, the last serving gNB may provide the WTRU context data. At 4 / 5, the gNB and WTRU may complete the RRC connection resumption. If grants permit, user data may be sent at 5. At 6, the gNB may provide a forwarding address if loss of buffered DL user data at the last serving gNB can be prevented. At 7 / 8, the gNB may perform a path switch. At 9, the gNB may trigger the release of WTRU resources at the last serving gNB. After 1 above, SRB0 (no security) may be used when the gNB rejects the resume request using a single RRC message (e.g., immediately) and decides, for example, to keep the WTRU in RRC_INACTIVE without reconfiguration (e.g., as described in the two examples below), or when the gNB decides to set up a different RRC connection (e.g., a new RRC connection). Conversely, SRB1 may be used (with integrity protection and encryption as previously configured for that SRB) when the gNB decides to reconfigure the WTRU (e.g., a new DRX cycle or RNA) or when the gNB decides to push the WTRU into RRC_IDLE. SRB1 may be used (e.g., only used) once the WTRU context may be retrieved (e.g., after 3).

[0111] FIG. 6 is an example of a WTRU-triggered transition from RRC_INACTIVE to RRC_CONNECTED (WTRU context retrieval failure). FIG. 6 illustrates a WTRU-triggered transition from RRC_INACTIVE to RRC_CONNECTED when WTRU context retrieval fails. At 1, the WTRU may resume from RRC_INACTIVE if an I-RNTI was assigned by the last serving gNB. At 2, the gNB may request the last serving gNB to provide the WTRU context data if it can resolve the gNB identity included in the I-RNTI. At 3, the last serving gNB may not retrieve or verify the WTRU context data. At 4, the last serving gNB may indicate a failure to the gNB. At 5, the gNB may perform a fallback to establish a different RRC connection (e.g., a new RRC connection) by sending RRCSetup. At 6, a different connection (e.g., a new connection) may be set up.

[0112] Figure 7 is an example of a rejection from the network when a WTRU attempts to resume a connection. Figure 7 illustrates a rejection from the network when a WTRU attempts to resume a connection from RRC_INACTIVE. At 1, the WTRU may attempt to resume a connection from RRC_INACTIVE. At 2, the gNB may not be able to process the procedure, for example, due to congestion. At 3, the gNB may send an RRC Reject (with a waiting time) to keep the WTRU in RRC_INACTIVE.

[0113] A network-triggered transition from RRC_INACTIVE to RRC_CONNECTED may occur. Figure 8 is an example of a network-triggered transition from RRC_INACTIVE to RRC_CONNECTED. Figure 8 illustrates a network-triggered transition from RRC_INACTIVE to RRC_CONNECTED. At 1, a RAN paging trigger event may occur (incoming DL user plane, DL signaling from 5GC, etc.). At 2, RAN paging may be triggered (e.g., only in cells controlled by the last serving gNB, or also by Xn RAN paging in cells controlled by other gNBs configured for the WTRU in a RAN-based notification area (RNA)). At 3, the WTRU may be paged using an I-RNTI. At 4, if the WTRU is successfully reached, the WTRU may attempt to resume from RRC_INACTIVE.

[0114] An RNA update may be performed. Figure 9 is an example of an RNA update procedure with WTRU context relocation. Figure 9 illustrates a WTRU-triggered RNA update procedure with context retrieval via Xn. This procedure may be triggered when the WTRU exits the configured RNA or periodically. In 1, the WTRU may resume from RRC_INACTIVE if the I-RNTI was assigned by the last serving gNB and with an appropriate cause value, e.g., RAN notification area update. In 2, if the gNB can resolve the gNB identity included in the I-RNTI, it may request the last serving gNB to provide the WTRU context if a cause value was received in 1. In 3, the last serving gNB may provide the WTRU context (as assumed below). Alternatively, the last serving gNB may decide to move the WTRU to RRC_IDLE (procedure follows from 3 in Figure 11), or, if the WTRU may still be in a previously configured RNA, may decide to keep the WTRU context at the last serving gNB and keep the WTRU in RRC_INACTIVE (procedure follows from 3 in Figure 10). At 4, the gNB may move the WTRU to RRC_CONNECTED (procedure follows from 4 in Figure 5), or may send the WTRU back to RRC_IDLE (in which case an RRC release message may be sent by the gNB), or the WTRU may be sent back to RRC_INACTIVE as assumed below. At 5, the gNB may provide a forwarding address if loss of buffered DL user data at the last serving gNB can be prevented. At 6 / 7, the gNB may perform a path switch. At 8, the gNB may keep the WTRU in RRC_INACTIVE state by sending an RRC release with an interruption indication. At 9, the gNB may trigger the release of WTRU resources at the last serving gNB.

[0115] Figure 10 is an example of a periodic RNA update procedure without WTRU context relocation. Figure 10 illustrates the RNA update procedure when the WTRU may still be in a configured RNA and the last serving gNB decides not to relocate the WTRU context and keep the WTRU in RRC_INACTIVE. In 1, the WTRU may resume from RRC_INACTIVE if the I-RNTI was assigned by the last serving gNB and with an appropriate cause value, e.g., RAN notification area update. In 2, if the gNB can resolve the gNB identity included in the I-RNTI, it may request the last serving gNB to provide the WTRU context if a cause value was received in 1. In 3, the last serving gNB may store the received information (e.g., the cell RNTI and physical cell ID (PCI) related to the resumption cell) to be used in the next resumption attempt and may respond to the gNB with a RETRIEVE UE CONTEXT FAILURE message including an encapsulated RRC release message. The RRC release message may include a suspension indication. At 4, the gNB may forward the RRC release message to the WTRU.

[0116] Figure 11 is an example of an RRC update procedure involving a transition to RRC_IDLE. Figure 11 illustrates the RRC update procedure when the last serving gNB decides to move the WTRU to RRC_IDLE. At 1, the WTRU may resume from RRC_INACTIVE if the I-RNTI was assigned by the last serving gNB and with an appropriate cause value, e.g., RAN Notification Area Update. At 2, if the gNB can resolve the gNB identity included in the I-RNTI, it may request the last serving gNB to provide the WTRU context if a cause value was received at 1. At 3, instead of providing the WTRU context, the last serving gNB may provide an RRC release message to move the WTRU to RRC_IDLE. At 4, the last serving gNB may delete the WTRU context. At 5, the gNB may send an RRC release that triggers the WTRU to move to RRC_IDLE.

[0117] A resume request responded with release with redirection with WTRU context relocation may be used. Figure 12 is an example of a resume request responded with release with redirection with WTRU context relocation. Figure 12 illustrates a WTRU-triggered NAS procedure responded by the network with release with redirection with WTRU context relocation. At 1, the WTRU may resume from RRC_INACTIVE if the I-RNTI was assigned by the last serving gNB. At 2, the gNB may request the last serving gNB to provide the WTRU context data if it can resolve the gNB identity included in the I-RNTI. At 3, the last serving gNB may provide the WTRU context. At 4, the gNB may move the WTRU to RRC_CONNECTED (procedure follows 4 in Figure 5), or may send the WTRU back to RRC_IDLE (in which case an RRC release message may be sent by the gNB), or may send the WTRU back to RRC_INACTIVE, including a release with a redirection indicator (as assumed below). At 5, the gNB may provide a forwarding address if loss of buffered DL user data at the last serving gNB can be prevented. At 6 / 7, the gNB may perform a path switch. At 8, the gNB may keep the WTRU in RRC_INACTIVE state by sending an RRC release with a suspension indication including redirection information (frequency layer that performs cell selection when the WTRU enters RRC_INACTIVE). At 9, the gNB may trigger release of WTRU resources at the last serving gNB. Upon receiving release with redirection, higher layers may trigger pending procedures so that the WTRU may attempt to resume again after cell selection.

[0118] Paging may be used. Paging may enable the network to reach WTRUs in RRC_IDLE and RRC_INACTIVE states through paging messages and to notify WTRUs in RRC_IDLE, RRC_INACTIVE, and RRC_CONNECTED states of system information changes and earthquake and tsunami warning system (ETWS) / commercial mobile alert system (CMAS) indicators through short messages. Both paging messages and short messages may be addressed using a paging (P)-RNTI on the physical downlink control channel (PDCCH) (e.g., the former may be sent on the PCCH, while the latter may be sent directly on the PDCCH).

[0119] While in RRC_IDLE, the WTRU may monitor the paging channel for CN-initiated paging. While in RRC_INACTIVE with no ongoing SDT procedure, the WTRU may monitor the paging channel for RAN-initiated paging and CN-initiated paging. The WTRU may not need to continuously monitor the paging channel; paging DRX may be where a WTRU in RRC_IDLE or RRC_INACTIVE may (e.g., only be required to) monitor the paging channel during one paging occasion (PO) per DRX cycle. The paging DRX cycle may be configured by the network. For CN-initiated paging, the default cycle may be broadcast in the system information; for CN-initiated paging, a WTRU-specific cycle may be configured via NAS signaling; for RAN-initiated paging, the WTRU-specific cycle may be configured via RRC signaling (e.g., the WTRU may use the shortest of the applicable DRX cycles; e.g., a WTRU in RRC_IDLE may use the shortest of the first two cycles above, and a WTRU in RRC_INACTIVE may use the shortest of the three cycles).

[0120] The WTRUs' POs for CN-initiated paging and RAN-initiated paging may be based on the same WTRU ID, resulting in both POs overlapping. The number of different POs in a DRX cycle may be configurable via system information, and the network may distribute the WTRUs to those POs based on their IDs.

[0121] While in RRC_CONNECTED and while in RRC_INACTIVE with an ongoing small data transmission (SDT) procedure, the WTRU may monitor the paging channel at (e.g., any) PO signaled in the system information for SI change indication and public warning system (PWS) notification. In case of bandwidth adaptation (BA), a WTRU in RRC_CONNECTED may monitor (e.g., only monitor) the paging channel on an active BWP with a common search space configured.

[0122] When operating with shared spectrum channel access, the WTRU may be configured for an additional number of PDCCH monitoring opportunities in its PO to monitor paging. If the WTRU detects a PDCCH transmission within the PO of the WTRU addressed with the P-RNTI, the WTRU may not need to monitor subsequent PDCCH monitoring opportunities within this PO.

[0123] If a paging reason may be included in a paging message, a WTRU in RRC_IDLE or RRC_INACTIVE state may use the paging reason.

[0124] Paging optimization for a WTRU in CM_IDLE may be performed. Upon WTRU context release, the NG-RAN node may provide a list of recommended cells and NG-RAN nodes to the AMF as assistance information for subsequent paging. The AMF may also provide paging attempt information including a paging attempt count and the intended number of paging attempts, and may include the next paging area range. If the paging attempt information may be included in the paging message, the (e.g., each) paged NG-RAN node may receive the same information during the paging attempt. The paging attempt count may be incremented by 1 for (e.g., each) new paging attempt. The next paging area range, if present, may indicate whether the AMF plans to modify the currently selected paging area for the next paging attempt. If the WTRU changes its state to CM CONNECTED, the paging attempt count may be reset.

[0125] Paging optimization for a WTRU in RRC_INACTIVE may be performed. In RAN paging, the serving NG-RAN node may provide RAN paging area information. The serving NG-RAN node may also provide RAN paging attempt information. The (e.g., each) paged NG-RAN node may receive the same RAN paging attempt information during a paging attempt, with the following contents: paging attempt count, intended number of paging attempts, and next paging area range. The paging attempt count may be incremented by 1 in (e.g., each) new paging attempt. The next paging area range, if present, may indicate whether the serving NG-RAN node plans to modify the currently selected RAN paging area in the next paging attempt. When the WTRU leaves the RRC_INACTIVE state, the paging attempt count may be reset.

[0126] WTRU power savings for paging monitoring may be used. To reduce WTRU power consumption due to false paging alarms, a group of WTRUs monitoring the same PO may be further divided into multiple subgroups. With subgrouping, a WTRU may monitor the PDCCH in that PO for paging if the subgroup to which it belongs can be paged as indicated via the associated PEI. If the WTRU cannot find its subgroup ID with the PEI configuration in the cell, or if the WTRU may not be able to monitor the associated PEI opportunity corresponding to that PO, the WTRU may monitor for paging in that PO. These subgroups may have the following characteristics: may be formed based on either CN-controlled subgrouping or WTRU ID-based subgrouping; if a CN-controlled subgroup ID cannot be provided from the AMF, WTRU ID-based subgrouping may be used if supported by the WTRU and the network; the RRC state (e.g., RRC_IDLE or RRC_INACTIVE state) may not affect which subgroup the WTRU belongs to; subgrouping support for a cell may be broadcast in the system information as one of the following (e.g., only CN-controlled subgrouping is supported, only WTRU ID-based subgrouping is supported, or both CN-controlled subgrouping and WTRU ID-based subgrouping are supported); the total number of subgroups allowed in a cell may be up to 8 and may represent the sum of CN-controlled subgrouping and WTRU ID-based subgrouping configured by the network; a WTRU with a CN-controlled subgroup ID configured may apply the CN-controlled subgroup ID if the cell supports CN-controlled subgrouping; otherwise, it may derive a WTRU ID-based subgroup ID (e.g., if the cell does not support WTRU ID-based subgrouping). only supports ID-based subgrouping).

[0127] The PEI associated with a subgroup may have the following characteristics: If the PEI may be supported by the WTRU, it may at least support the WTRU ID-based subgrouping method; PEI monitoring may be limited to the cell from which its last connection was released via system information (e.g., unless the network indicates that the WTRU does not update its last used cell information); a PEI-enabled WTRU may store its last used cell information; a gNB that supports PEI monitoring for last used cell functionality may provide the WTRU's last used cell information to the AMF in the NG-AP UE Context Release Complete message for the PEI-enabled WTRU; a WTRU expecting multicast and broadcast service (MBS) group notification may ignore the PEI and monitor its PO for paging.

[0128] CN-controlled subgrouping may be used. For CN-controlled subgrouping, the AMF may be responsible for allocating subgroup IDs to WTRUs. For example, the total number of subgroups for CN-controlled subgrouping, which may be configured by operations, administration, and maintenance (OAM), may be up to a certain number (e.g., 8). It may be assumed that CN-controlled subgrouping support may be uniform within the RNA.

[0129] Figure 13 is an example procedure for CN-controlled subgrouping. Figure 13 illustrates a procedure for CN-controlled subgrouping. At 1, the WTRU may indicate its support for CN-controlled subgrouping via NAS signaling. At 2, if the WTRU supports CN-controlled subgrouping, the AMF may determine a subgroup ID allocation for the WTRU. At 3, the AMF may send the subgroup ID to the WTRU via NAS signaling. At 4, the AMF may inform the gNB about the subgroup ID allocated by the CN to page the WTRU in RRC_IDLE / RRC_INACTIVE state. At 5, when a paging message for the WTRU may be received from the CN or generated by the gNB, the gNB may determine a PO and associated PEI opportunity for the WTRU. At 6, before the WTRU can be paged at the PO, the gNB may send an associated PEI and indicate the corresponding CN-controlled subgroup of the WTRU to be paged at the PEI.

[0130] WTRU ID-based subgrouping may be used. For WTRU ID-based subgrouping, the gNB and WTRU may determine a subgroup ID based on the WTRU ID and the total number of subgroups for WTRU ID-based subgrouping in the cell. The total number of subgroups for WTRU ID-based subgrouping may be determined by the gNB for (e.g., each) cell and may be different in different cells. Figure 14 is an example procedure for WTRU ID-based subgrouping. Figure 14 illustrates a procedure for WTRU ID-based subgrouping. In step 1, the gNB may determine the total number of subgroups for WTRU ID-based subgrouping in the cell. In step 2, the gNB may broadcast the total number of subgroups for WTRU ID-based subgrouping in the cell. In step 3, when a paging message for a PEI-enabled WTRU may be received from the CN at the gNB or generated by the gNB, the gNB may determine a PO and an associated PEI opportunity for the WTRU. At 4, before a WTRU may be paged at the PO, the gNB may send an associated PEI and indicate a corresponding subgroup derived based on the WTRU ID of the WTRU that may be paged at the PEI.

[0131] Extended DRX for RRC_IDLE and RRC_INACTIVE may be used. When extended DRX (eDRX) may be used, the following may apply: For RRC_INACTIVE, the eDRX configuration for RAN paging may be determined and configured by NG-RAN. In RRC_INACTIVE, the WTRU may monitor both RAN and CN paging. For RRC_IDLE, eDRX for CN paging may be configured by higher layers. In RRC_IDLE, the WTRU may monitor CN paging (e.g., only CN paging). Information about whether eDRX is allowed on a cell for WTRUs in RRC_IDLE and RRC_INACTIVE may be provided separately for RRC_IDLE and RRC_INACTIVE in the system information. The maximum value of the eDRX cycle may be 10485.76 seconds (2.91 hours) for RRC_IDLE and 10.24 seconds for RRC_INACTIVE, and the minimum value of the eDRX cycle may be 2.56 seconds for both RRC_IDLE and RRC_INACTIVE. The hyper system frame number (H-SFN) may be broadcast by the cell and increment by 1 when the SFN wraps around; the paging hyperframe (PH) may refer to the H-SFN at which the WTRU starts monitoring paging DRX during the paging time window (PTW) used in RRC_IDLE. The PH and PTW may be determined based on formulas that may be known by the AMF, the WTRU, and the NG-RAN. If the eDRX cycle can be longer than 10.24 seconds, the H-SFN, PH, and PTW may be used. When the eDRX cycle may be longer than the system information modification period, the WTRU may verify that the stored system information remains valid before establishing an RRC connection.

[0132] NR NTN (non-terrestrial network) extensions (e.g., NTN-TN and NTN-NTN mobility and service continuity extensions) may include one or more of the following: NTN-TN and NTN-NTN measurement / mobility and service continuity extensions may be specified. For NTN-NTN mobility, cell reselection for terrestrial mobile cells (e.g., cell reselection extensions), timing-based and / or location-based cell reselection for semi-terrestrial fixed cells may be considered. To reduce signaling overhead, NTN-NTN handover for RRC_CONNECTED WTRUs in semi-terrestrial fixed cells and / or terrestrial mobile cells (e.g., NTN-NTN handover extensions) may be specified. To reduce WTRU power consumption (NTN-TN mobility may be prioritized), cell reselection for RRC_IDLE / INACTIVE WTRUs (e.g., cell reselection extensions) may be specified. Extensions to Xn[ / NG] signaling to support feeder link handover (CHO), e.g., exchange of information such as required information between gNBs, may be specified.

[0133] The network may include several layers (e.g., TN and one or more of LEO, MEO, and GEO satellites), which may operate with different cell sizes and different over-the-air propagation delays (e.g., each of the layers may operate with different cell sizes and / or different over-the-air propagation delays). Figure 15 is an example of an NTN-TN network layer. In an example (e.g., the example shown in Figure 15), GEO (e.g., satellite or cell) may have the largest cell coverage (e.g., the longest propagation delay) among TN, LEO, MEO, and GEO, followed by MEO, then LEO, which may have smaller cell coverage and / or shorter propagation delay than GEO and MEO, and TN, which may have the smallest cell coverage and shortest propagation delay among TN, LEO, MEO, and GEO.

[0134] Although one or more examples herein may refer to TN to NTN coverage, the principles, processes, means, and systems may be applied to any combination of network layers (e.g., LEO to GEO, TN to MEO to GEO, etc.).

[0135] If TN and NTN coverage are available to a WTRU, the WTRU may camp on an NTN cell, which may advantageously provide benefits in terms of WTRU power savings, for example, even when the WTRU is in an RRC_INACTIVE state (e.g., mode / operating condition). In an example, an NTN cell may have wider coverage than a TN cell (or multiple TN cells combined) (e.g., as shown in FIG. 15), which may minimize one or more of the following (e.g., particularly for a mobile WTRU): neighbor cell measurements; cell reselection; system information (SI) readings.

[0136] The WTRU may camp on an NTN cell, which may provide further benefits, e.g., in terms of NW paging load. For example, if TN coverage and NTN coverage are available to the WTRU, the WTRU may camp on an NTN cell, e.g., when the WTRU is in an RRC inactive state. One or more cell reselection techniques described in one or more examples used for a WTRU in an RRC_INACTIVE state may be used for a WTRU in an RRC_IDLE state (e.g., the same or similar cell reselection method may be used for both RRC_IDLE and RRC_INACTIVE; e.g., different parameters (e.g., cell reselection priority, thresholds) may be configured, but the process may be the same or similar). In an example, when the NTN cell has wider coverage than the TN cell or multiple TN cells combined (e.g., as shown in FIG. 15), the WTRU cell location (e.g., the cell on which the WTRU is camped) may be known and / or easier to obtain. For example, when the WTRU cell location is known, or known with higher confidence (e.g., based on higher likelihood, higher statistical probability, or increased reliability of the associated metric), paging may not need to be spread across multiple cells in the RNA. In an example, in a TN cell, the WTRU may perform cell reselection in RRC_INACTIVE state in the RNA, e.g., without notifying the network. The network may page in multiple cells, e.g., to find the WTRU's location. In some examples, in an NTN cell with relatively wide coverage (e.g., a GEO satellite), the cell location associated with the WTRU may be known or more likely to be known, e.g., because the WTRU may not need to reselect to another cell. In an NTN cell with medium coverage (e.g., another NTN cell, such as a LEO, Earth mobile, etc.), the cell location may be known with higher confidence (e.g., there may be a limited number of potential cells on which the WTRU may camp, compared to a TN, for example).For example, in an NTN cell with moderate coverage, the cell location may be known with more confidence even in the case of cell reselection within the TA / RNA (e.g., because the WTRU may not be moving significantly within the geographic area). In one or more examples herein, the WTRU cell location may refer to the cell, carrier, band, subband, and / or BWP on which the WTRU is camped.

[0137] If TN and NTN coverage are available to the WTRU, the WTRU may camp on a TN cell, which may advantageously provide benefits, e.g., in terms of latency. In some examples, a TN cell may be a better choice than an NTN cell, e.g., in terms of signaling delay and / or data throughput (e.g., RRC resumption procedures and / or data transfers may experience long propagation delays in NTN cells). Notification and / or delivery of paging messages may be subject to latency in NTN cells (e.g., potentially long, or longer than when TN cells are used). The NTN cell may still be used for paging message delivery (e.g., delays may not always be worse on NTN cells, considering potential paging escalation).

[0138] For example, there may be differences (e.g., differences that pose challenges compared to the RRC_IDLE state) between the RRC_INACTIVE state and the RRC_IDLE state due to the WTRU being in CM-CONNECTED (e.g., connected to the core network). A base station (e.g., a final serving base station such as a gNB) may hold a WTRU context and / or a WTRU-associated connection (e.g., a WTRU-associated NG connection with the serving AMF and / or UPF). Paging (e.g., RAN paging) may be initiated. For example, if the last serving gNB receives DL data from the UPF or DL ​​WTRU-related signaling from the AMF while the WTRU is in RRC_INACTIVE state (e.g., if the last serving gNB receives DL data or DL ​​WTRU-related signaling other than a WTRU context release command message), the last serving gNB may page in one or more of the cells corresponding to the RNA and / or send XnAP RAN paging to neighboring gNBs (e.g., if the RNA includes cells of neighboring gNBs, the last serving gNB may also page in those cells of the neighboring gNBs).

[0139] If a WTRU is camped on an NTN cell but is moving (e.g., such that the RNA of the TN may change), the DL data may already have been delivered to the last serving base station (e.g., a gNB in ​​the TN cell), and in some examples, if the WTRU is paged through an NTN cell, the data may not reach and / or be delivered to the WTRU, for example, at a gNB in ​​the RNA (e.g., any gNB), unless the NTN gNB may be part of the same RNA as the last connected TN gNB (e.g., this may or may not be due to the relatively large size of the NTN cell). One or more examples herein may use the term gNB, but may be applicable to any base station. The coverage of an NTN cell may cover multiple TN RNAs. An NTN cell in one or more examples herein may interchangeably be referred to as an NTN satellite.

[0140] In some examples, if a WTRU performs RNAU for the RNA of an NTN cell and / or remains in RRC_INACTIVE state, data delivery on the NTN cell may experience long latency (e.g., due to long propagation times on the NTN radio link).

[0141] Overlapping network layers (e.g., overlapping TN-NTN coverage) may be used, for example, to achieve power savings and / or paging load benefits in the NTN cell when the WTRU is in RRC_INACTIVE state (e.g., when the WTRU is in the TN and / or NTN), and / or may be used to deliver data via the TN cell, for example, to achieve better throughput and / or latency.

[0142] In an example, a WTRU in RRC_INACTIVE state (e.g., while the WTRU is camped on a TN cell and / or registered in a TN RNA) may be released to RRC_IDLE state to perform cell reselection to the NTN cell (e.g., to save power). The WTRU may be paged by the CN (e.g., by the CN only), and a different RRC connection (e.g., a new RRC connection) may be established on the NTN cell or may be established when the WTRU returns to the TN cell, e.g., based on a redirection or handover command from the NTN cell or an indicator in the paging message to respond on the TN cell. The WTRU may save power by camping on the NTN cell (e.g., by camping on an NTN cell, the WTRU may not always benefit from the latency advantages that can be obtained by being in RRC_INACTIVE state). Examples herein may be applicable to devices for which power savings are beneficial (e.g., devices that may require the latency advantages of the RRC_INACTIVE state in some cases or times and may require power savings in other cases or times). In examples, the device may include a wearable or portable device that may be in use at some instances or times and in standby mode at other instances or times.

[0143] 16 is an example of a release to RRC_IDLE for camping on an NTN. A WTRU (e.g., WTRU 1610) may send 1650 WTRU assistance information (e.g., UE assistance information) or an RRC release request, for example, to a base station (e.g., TN gNB 1620).

[0144] The WTRU may send WTRU assistance information (e.g., for the WTRU to be released to idle so that it can camp on the NTN cell). In an example, a WTRU (e.g., a WTRU in an RRC_CONNECTED state) may initiate transmission of WTRU assistance information including, for example, an indication that the WTRU prefers to camp on the NTN cell (e.g., to save power). In some examples, a WTRU (e.g., a WTRU in an RRC_INACTIVE state) may first perform an RRC connection resumption procedure, for example, to transmit the WTRU assistance information.

[0145] The WTRU may send an RRC release request (e.g., to be released to idle so that the WTRU camps on the NTN cell). In some examples, sending an RRC release request to transition from an RRC_INACTIVE state to an RRC_IDLE state may be more efficient than, for example, sending WTRU assistance information. The WTRU may send a message (e.g., Msg3, Msg5, or MsgA) or request, for example, when the WTRU is in the RRC_INACTIVE state. The message may include an RRC release request (e.g., Msg3, Msg5, or MsgA may include a new RRC message such as an RRC release request). The RRC release request may indicate or include an indicator to indicate that the WTRU prefers to camp on the NTN cell.

[0146] The RRC release request or WTRU assistance information may indicate or include an indication of the availability of the NTN cell. The WTRU may, for example, include in the RRC release request or WTRU assistance information one or more of the following: available measurement results of the NTN cell (e.g., measured via the TN); location information (e.g., coarse WTRU location); indications (e.g., 1 bit) of detected NTN cells that may be suitable (e.g., any detected NTN cell associated with measurements above a threshold or any detected NTN cell that meets a suitability criterion / criteria or condition); information about the satellites and / or NTN cells (e.g., including one or more of satellite ephemeris data, NTN deployment scenario, NTN cell reference point, satellite footprint information, neighbor satellite assistance information, detected NTN cell ID); information about time / frequency advance compensation to the NTN cell (e.g., the WTRU's timing advance via the Timing Advance MAC CE).

[0147] In response to receiving the RRC release request or the WTRU assistance information, the network (e.g., the TN gNB 1620) may transmit 1660 a message, e.g., an RRC release message, indicating a change from the RRC_INACTIVE state to the RRC_IDLE state. The RRC release message may include cell reselection priority information (e.g., transmission priority information). The cell reselection priority information may indicate a priority associated with one or more frequency layers associated with the NTN (e.g., the cell reselection priority information may indicate a higher priority allocated to the NTN frequency layer). The RRC release message may include a priority decrement indicator (e.g., a priority decrement indicator indicating a priority decrement for the current frequency layer or RAT, such that the current frequency layer or RAT may be considered a lower priority than other frequency layers or RATs). The RRC release message may include information indicating one or more of the following that the WTRU may use to perform redirection (e.g., the WTRU may attempt to camp on): a specific target frequency, a specific target band, a specific target cell, or a specific target network. The information provided in the RRC release message may include a time value (e.g., a timer value during which one or more parameters apply. For example, the parameters may include parameters in the RRC release such as a cell reselection priority validity timer and / or a priority decrement timer). For example, the information provided in the RRC release message may include a timer that specifies a period during which the WTRU may camp / prioritize the frequency layer of the NTN before resetting to use the broadcast priority value.

[0148] At 1670, the WTRU may perform reselection to the NTN (e.g., cell reselection to an NTN cell having the NTN gNB 1640), e.g., based on information provided in the RRC release message. The WTRU may monitor paging at the NTN (e.g., monitor paging messages from an NTN cell having the NTN gNB 1640). At 1680, the WTRU may receive a paging message from the NTN (e.g., from the NTN gNB 1640).

[0149] In an example, the WTRU may perform reselection to the NTN cell and remain in the RRC_INACTIVE state. In this case, a request (e.g., an RRC release request or WTRU assistance information described in one or more examples herein, such as the example shown in FIG. 16) may be used to request a network change (e.g., from a TN to an NTN or from an NTN to a TN). In an example, the WTRU may perform measurements associated with one or more NTN cells before changing from the RRC_CONNECTED state to the RRC_INACTIVE state and may send a request for cell reselection to the NTN cell based on the measurements. The WTRU may receive an indication to change from the TN cell to the NTN cell after the request is sent.

[0150] The WTRU may receive a suspension indication (e.g., SuspendConfig) along with an indication to change from the TN cell to the NTN cell, e.g., after the request has been sent. In an example, the configuration information (e.g., configuration information associated with the RRC release) may include SuspendConfig instead of information indicating, e.g., a release to the RRC_IDLE state. In some examples, the WTRU may be configured to perform reselection to the NTN cell and / or maintain RNA tracking over the TN while camped on the NTN cell (e.g., during the RRC connection and before the connection may be interrupted), e.g., as described in one or more examples herein.

[0151] TN-NTN interworking may be used, which may provide and / or enable one or more of the following: paging the WTRU via an NTN cell (e.g., by an NTN platform); responding to or being redirected to a TN cell (e.g., such that the WTRU may remain CM-CONNECTED and DL data received at the last used TN base station (e.g., gNB) may be delivered to the WTRU via the TN cell).

[0152] Figure 17 is an example of RNA alteration based on TN measurements. In Figure 17, WTRU 1710 may determine whether to perform RNA updating (e.g., RNA maintenance) of the TN while WTRU 1710 is camped on the NTN.

[0153] RNA may include multiple cells. As shown in FIG. 17, RNA2 may include multiple cells, including cell 1750 and cell 1720. Cell 1750 and cell 1720 may be TN cells. WTRU 1710 may be in an area where cell 1720, cell 1730, and cell 1760 have coverage, as shown in FIG. 17. Cell 1720 may be associated with RNA2. Cell 1730 may be associated with RNA3. Cell 1760 may be associated with RNA3. The WTRU may perform cell measurements for cell selection or reselection.

[0154] For example, the WTRU 1710 may initially select the cell 1730 associated with RNA3. The WTRU 1710 may perform cell reselection to the NTN cell 1746, for example, as shown in one or more examples herein. The WTRU may camp on the NTN cell 1746 (e.g., using the NTN cell 1746 to monitor paging from the NTN platform 1740, etc.). For example, the WTRU may receive an indication to change from a TN (e.g., the cell 1730 associated with RNA3) to an NTN (e.g., the NTN cell 1746). The WTRU may perform cell reselection to the NTN cell 1746 based on the received indication. The WTRU may receive an indication to change from an RRC_CONNECTED state to an RRC_INACTIVE state, for example, together with or separately from the indication to change from the TN cell to the NTN. The WTRU may be released to the RRC_INACTIVE state while camped on the NTN cell. The WTRU may perform measurements, for example, to determine whether cell reselection should be performed. The measurements may be associated with different cells and / or RNAs. As shown in FIG. 17, the WTRU may perform TN measurements, for example, while the WTRU is camped on an NTN cell 1746. The WTRU 1710 may evaluate one or more TN cells, for example, based on the TN measurements. The WTRU 1710 may, for example, perform measurements associated with RNA2 (e.g., measurements of the cell associated with RNA2 1720) and measurements associated with RNA3 (e.g., measurements of the cell associated with RNA3 1730 and / or measurements of the cell associated with RNA3 1760) while the WTRU is camped on the NTN cell 1746. The WTRU 1710 may determine that a cell reselection condition is satisfied (e.g., a cell reselection condition is met or fulfilled). The cell reselection condition may be a TN cell reselection condition. The cell reselection condition may be associated with the cell 1720 associated with RNA2. For example, the WTRU 1710 may move to a location that is better covered by RNA2 than RNA3, and / or the measurement value associated with the cell 1720 associated with RNA2 may be greater than a predetermined value.The WTRU 1710 may perform cell reselection to the cell 1720 associated with RNA2.

[0155] A WTRU may register with one or more RNAs. In an example, a WTRU may register with at least two RNAs (e.g., a first RNA associated with a TN and a second RNA associated with an NTN). In some examples, a WTRU may register to use a first RNA associated with a TN and a second RNA associated with an NTN. The WTRU may register with the first RNA associated with a TN and the second RNA associated with an NTN (e.g., simultaneously) before the WTRU performs cell reselection to an NTN cell and / or transitions from an RRC_CONNECTED state to an RRC_INACTIVE state.

[0156] In some examples, a first RNA associated with a TN and an NTN cell, or a first RNA associated with a TN and a second RNA associated with an NTN, may be associated. In this manner, a WTRU may be paged (e.g., by receiving a paging message) via the NTN cell associated with the first RNA, and / or the WTRU may respond to a paging (e.g., in response to receiving a paging message) via the TN cell associated with the first RNA. For example, the network may associate a TN RNA with an NTN cell (or NTN RNA) such that when DL data arrives at the TN gNB last used by the WTRU, the network may page the WTRU via the NTN cell, so that the WTRU responds via the TN cell (e.g., the TN cell associated with the TN RNA). From the CN's perspective, the WTRU may be in the TN cell (e.g., even when the WTRU is paged via the NTN cell). The TN base station may notify the NTN cell (e.g., the NTN cell associated with the TN cell) when the TN base station has data to be transmitted to the WTRU. For example, when data arrives, the TN gNB may notify an associated NTN gNB, e.g., via X2 / Xn. The WTRU may be paged (e.g., RAN paged) in the NTN RNA or NTN cell. The WTRU may respond (e.g., based on receipt of the paging message) in the TN cell.

[0157] The WTRU may measure and / or evaluate one or more TN cells, e.g., for cell reselection. The measurement and / or evaluation of one or more TN cells may be performed when the WTRU camps on an NTN cell, e.g., after cell reselection to the NTN cell is performed. The WTRU may determine that a cell reselection condition (e.g., cell reselection criteria for the TN cell) is satisfied. For example, an RNA change in the TN may be performed based on the measurement and / or evaluation of one or more TN cells. In an example, while the WTRU is camped on an NTN cell, the WTRU may measure and / or evaluate cell reselection criteria associated with the TN, e.g., such that one or more suitable base stations (e.g., the correct gNB or gNBs in the TN RNA in which the WTRU may be geographically located) are used to receive data from and / or send data to the WTRU.

[0158] The WTRU may receive identification information associated with one or more RNAs (e.g., TN RNAs). The WTRU may receive cell identification information associated with an RNA. For example, the WTRU may receive a list of cell identification information belonging to a TN RNA, a list of cell identification information belonging to multiple TN RNAs, or multiple lists of cell identification information belonging to multiple TN RNAs (e.g., a respective list of cell identification information for each of the TN RNAs).

[0159] The WTRU may receive information regarding a cell reselection condition associated with a TN cell associated with an RNA, a cell reselection condition associated with a TN cell associated with an RNA, or a cell reselection condition associated with a TN cell associated with multiple RNAs. For example, the WTRU may receive cell reselection criteria corresponding to a cell. In an example, the cell reselection criteria may include thresholds and / or priorities relating to cells on a frequency, e.g., some or all cells on a frequency. The cell reselection criteria may include cell reselection thresholds (e.g., predetermined cell measurements). The cell reselection criteria may include cell reselection priority information (e.g., predetermined priority levels associated with a cell or frequency). In an example, the cell reselection criteria may include cell-specific information for each cell (e.g., each cell).

[0160] Identification information associated with one or more RNAs and / or cells may be received, for example, via RRC signaling. One or more cell reselection conditions may be received, for example, via RRC signaling. Identification information associated with one or more RNAs and / or cells may be received in the TN or NTN. One or more cell reselection conditions may be received in the TN or NTN. In examples, a list of cell identities associated with (e.g., belonging to) one or more TN RNAs and / or cell reselection criteria (e.g., cell reselection thresholds and / or priorities) corresponding to a cell may be received in broadcast signaling or dedicated signaling (e.g., dedicated RRC signaling). A list of cell identities associated with one or more TN RNAs and / or cell reselection criteria corresponding to a cell may be received via a TN cell or via an NTN cell. In some examples, a list of cell identities associated with one or more TN RNAs and / or cell reselection criteria corresponding to a cell may be received and / or stored from a TN cell via broadcast system information.

[0161] The WTRU may, for example, evaluate one or more cells of a first network while the WTRU is camped on a second network. The WTRU may evaluate a virtual cell reselection status of the first network. For example, the WTRU may evaluate the cell reselection status of the first network when the WTRU is camped on the second network as if it were camped on the first network. For example, while camped on an NTN cell, the WTRU may determine the virtual cell reselection status of the NTN based on one or more of the following: TN cell reselection information (e.g., stored TN cell reselection information); RNA and / or cell information; and measurement results. The TN cell reselection information may include, for example, cell reselection conditions. The RNA and / or cell information may include, for example, identification information associated with one or more RNAs and / or cells. The WTRU may perform one or more of the following as if the WTRU were camped on a TN cell (e.g., even though the WTRU may be camped on an NTN cell): measurements of one or more TN cells; evaluation of cell reselection criteria for the TN cells; determination of whether cell reselection to one or more of the TN cells should be performed.

[0162] The WTRU may not perform cell reselection (e.g., any cell reselection), for example, if the RNA associated with the WTRU is not changed. In some examples, the WTRU may evaluate cell reselection criteria without triggering cell reselection (e.g., the WTRU may only evaluate cell reselection criteria).

[0163] If the WTRU determines that cell reselection to the TN cell may result in a change of RNA, the WTRU may notify the base station (e.g., NTN gNB) of the RNA change (e.g., a message indicating "RNA change in TN"). The WTRU may send an indication of the change from the first RNA to the second RNA to the base station. The WTRU may be released to the RRC_IDLE state (e.g., before or without cell reselection to a TN cell associated with a different RNA). The base station may send an indication to the WTRU to change from the RRC_INACTIVE state to the RRC_IDLE state, e.g., in response to the indication of the RNA change sent by the WTRU. The WTRU may receive, e.g., from the base station, an indication to change from the RRC_INACTIVE state to the RRC_IDLE state. In some examples, when the WTRU operates in the RRC_IDLE state, DL data may no longer be delivered to the WTRU in the TN (e.g., because the WTRU may no longer be in the same RNA).

[0164] In an example, if the WTRU determines that cell reselection to a TN cell may result in a change in RNA, the WTRU may initiate and / or perform an RNA update, e.g., via the NTN. In an example, the WTRU may initiate an RNA update procedure (e.g., an RNA update procedure as described in one or more examples herein) and perform signaling via the NTN cell.

[0165] In some examples, if the WTRU determines that cell reselection to a TN cell may result in a change of RNA, the WTRU may perform cell reselection to a cell associated with a different RNA. In examples, the WTRU may initiate cell reselection to a TN cell associated with a different RNA and / or trigger an RNA update in the TN itself. The WTRU may return to camping on the NTN again, for example, after the WTRU receives a data transmission from a TN cell associated with a different RNA.

[0166] Using one or more examples herein, a WTRU may camp on an NTN cell to avoid cell reselection in the TN RNA and / or may perform cell reselection (e.g., perform cell reselection only when necessary) to update the TN RNA if the TN RNA changes. When service is initiated, the WTRU may be paged on the NTN cell (e.g., by receiving a paging message) and / or respond to the page via the TN cell. One or more examples herein may enjoy the power saving benefits of reduced cell reselection (e.g., benefit of camping on an NTN) and improved latency benefits (e.g., reduced latency by performing most of the data delivery and / or signaling on the TN cell).

[0167] For example, several measurement conditions may be used for measurements on the TN while camped on the NTN. In an example, if the NTN is associated with a frequency layer of higher priority than the TN and the NTN cell is of suitable quality, the WTRU may not need to perform measurements on the TN cell. In some examples, even if the NTN is associated with a frequency layer of higher priority than the TN and the NTN cell is of suitable quality, the WTRU may perform measurements on one or more TN cells (e.g., TN cells associated with a lower priority than the NTN cell). As an example, a condition may be to perform measurements on one or more TN cells or carriers according to a higher priority frequency requirement (e.g., a higher priority frequency requirement associated with the NTN), even if the TN cell or carrier is assigned a lower priority. The WTRU may perform measurements at a certain rate (e.g., a rate higher than high-priority frequency measurements and lower than coverage-based measurements, such as requirements that apply when the serving cell coverage is below a threshold).

[0168] FIG. 18 is an example of an RNA change based on TN measurements. In FIG. 18, the WTRU 1810 may determine whether to perform an RNA update (e.g., RNA maintenance) for the TN while the WTRU 1810 is camped on the NTN. At 1850, the WTRU 1810 may be released to an RRC_INACTIVE state with an indication to move to the NTN (e.g., to the NTN gNB 1840). At 1850, the network (e.g., the TN gNB 1820) may send a message indicating a change to the RRC_INACTIVE state (e.g., an indication associated with an RRC release, such as an interrupt indication). The WTRU 1810 may receive the indication to change to the RRC_INACTIVE state. The WTRU 1810 may initiate a change to the RRC_INACTIVE state (e.g., from an RRC_CONNECTED state to an RRC_INACTIVE state), for example, based on the indication to change to the RRC_INACTIVE state.

[0169] The message may include an indication to move to the NTN. The WTRU may initially select (e.g., perform cell selection to) a TN cell associated with RNA1, e.g., the TN gNB 1820. The indication to move to the NTN may include an indication to change from a TN cell to an NTN cell. For example, the WTRU may send a request to, e.g., the TN gNB 1820, to change from the TN cell to the NTN cell. In response to the request, the TN gNB 1820 may send an indication to the WTRU 1810 to change from the TN cell to the NTN cell.

[0170] In an example, the WTRU 1810 may receive separate indicators at different times (e.g., a first indicator indicating a change from a TN cell to an NTN cell and a second indicator indicating a change from an RRC_CONNECTED state to an RRC_INACTIVE state). The WTRU 1810 may receive the separate indicators simultaneously. The WTRU 1810 may receive an indicator indicating a change from a TN cell to an NTN cell and an indicator indicating a change from an RRC_CONNECTED state to an RRC_INACTIVE state. In some examples, the indicator for changing to the RRC_INACTIVE state may be used as an indicator for changing from the TN cell to the NTN cell. For example, the WTRU 1810 may initiate a change from the TN cell to the NTN cell based on receiving the indicator for changing to the RRC_INACTIVE state.

[0171] At 1870, the WTRU 1810 may perform cell reselection to an NTN cell (e.g., the NTN gNB 1840) and / or monitor for paging on the NTN cell. The WTRU 1810 may perform cell reselection to the NTN cell based on, for example, an indicator indicating a change from the TN cell to the NTN cell. The WTRU 1810 may monitor for paging messages on the NTN cell after, for example, the WTRU 1810 performs cell reselection to the NTN cell.

[0172] The WTRU 1810 may receive a paging message from the NTN cell, for example, when the WTRU is operating in an RRC_INACTIVE state. The WTRU 1810 may initiate a change from the RRC_INACTIVE state to the RRC_CONNECTED state based on the receipt of the paging message. The WTRU 1810 may receive a data transmission from a second TN cell in the RRC_CONNECTED state.

[0173] At 1880, the WTRU 1810 may evaluate one or more cells, e.g., during a time period associated with the WTRU 1810 being configured to monitor a paging message from an NTN cell. For example, at 1880, while the WTRU 1810 is monitoring a paging message from an NTN cell, the WTRU 1810 may perform measurements of TN cells in RNA1 and RNA2, which may include a TN gNB 1820 associated with RNA1 and a TN gNB 1830 associated with RNA2. The WTRU 1810 may evaluate one or more cells before the WTRU 1810 receives a paging message from the NTN cell and at a time after the WTRU 1810 performs cell reselection to the NTN cell. The WTRU 1810 may stop monitoring for paging, e.g., after the WTRU 1810 receives a paging message from the NTN cell. The WTRU 1810 may resume monitoring for paging in the NTN, for example, when the WTRU 1810 performs cell selection / reselection to the NTN cell after the WTRU 1810 receives a data transmission from the TN gNB 1830 associated with RNA2.

[0174] The WTRU 1810 may determine a virtual cell reselection status for the TN, for example, during a time period associated with the WTRU 1810 being configured to monitor paging messages from the NTN cell. Determining the virtual cell reselection status for the TN may include evaluating one or more TN cells and / or limiting the evaluation to one or more TN cells. For example, the evaluation of the one or more TN cells may include evaluating the TN gNB 1820 associated with RNA1 and / or evaluating the TN gNB 1830 associated with RNA2, and may be limited to TN cells (e.g., only TN cells). In some examples, the WTRU 1810 may evaluate cell reselection criteria without considering the current NTN cell (e.g., perform virtual cell reselection as if the WTRU were camped on the TN cell).

[0175] At 1890, the WTRU 1810 may determine that a condition (e.g., a cell reselection condition that causes cell reselection from a cell in RNA1 to a cell in RNA2) is met. The WTRU 1810 may determine that a cell reselection condition associated with the TN gNB 1830 is satisfied based on, for example, an evaluation of one or more TN cells including the TN gNB 1830. For example, the WTRU 1810 may determine that an RSRP associated with the TN gNB 1830 is greater than or equal to a cell reselection threshold. The WTRU 1810 may determine that a cell reselection priority associated with the TN gNB 1830 is preferred based on cell reselection priority information (e.g., transmission priority information) received in an RRC message. The WTRU may perform cell reselection to the TN gNB 1830 in RNA2 (e.g., cell reselection from an NTN cell to the TN gNB 1830 in RNA2).

[0176] At 1896, the WTRU may initiate an RNA update procedure (eg, an RNA update procedure from RNA1 to RNA2).

[0177] FIG. 19 illustrates an example 1900 for evaluation of one or more TN cells to determine an RNA update. At 1920, the WTRU may release from the TN gNB in ​​RNA1 to RRC_INACTIVE state with an indication to move to the NTN, e.g., as shown at 1850 in FIG. 18. At 1930, the WTRU may perform cell reselection to the NTN cell and monitor paging on the NTN cell, e.g., as shown at 1870 in FIG. 18. At 1940, the WTRU may perform measurements of TN cells in RNA1 and RNA2, e.g., as shown at 1880 in FIG. 18, and may evaluate cell reselection criteria without considering the current NTN cell (e.g., using virtual cell reselection as if the WTRU were camped on the TN). At 1950, the WTRU may determine that criteria are met that may cause cell reselection from a cell in RNA1 to a cell in RNA2, e.g., as shown at 1890 in FIG. 18. The WTRU may perform reselection from NTN to TN RNA2 (e.g., cell reselection from the NTN cell to the TN cell associated with RNA2), e.g., as shown at 1890 in Figure 18. At 1960, the WTRU may initiate an RNA update procedure for RNA2, e.g., as shown at 1890 in Figure 18.

[0178] Although the features and elements described above are described in particular combinations, each feature or element may be used alone without the other features and elements of the preferred embodiments, or may be used in various combinations with or without the other features and elements.

[0179] While implementations described herein may consider 3GPP-specific protocols, it will be understood that the implementations described herein are not limited to this scenario and may be applicable to other wireless systems. For example, while the solutions described herein consider LTE, LTE-A, New Radio (NR), or 5G-specific protocols, it will be understood that the solutions described herein are not limited to this scenario and may be applicable to other wireless systems. For example, while systems have been described with reference to 3GPP, 5G, and / or NR network layers, contemplated embodiments extend beyond implementations using specific network layer technologies. Similarly, potential implementations extend to some or all types of service layer architectures, systems, and embodiments. The techniques described herein may be applied independently and / or used in combination with other resource configuration techniques.

[0180] The processes described herein may be implemented in a computer program, software, and / or firmware embodied in a computer-readable medium for execution by a computer and / or processor. Examples of computer-readable media include, but are not limited to, electronic signals (transmitted via wired and / or wireless connections) and / or computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random-access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as, but not limited to, internal hard disks and removable disks, magneto-optical media, and / or optical media such as Compact Disc (CD)-ROM disks and / or Digital Versatile Disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, terminal, base station, RNC, and / or any host computer.

[0181] It is understood that the entities performing the processes described herein may be logical entities that may be implemented in the form of software (e.g., computer-executable instructions) stored in the memory of a mobile device, network node, or computer system and executed on its processor. That is, the processes may be implemented in the form of software (e.g., computer-executable instructions) stored in the memory of a mobile device and / or network node, such as a node or computer system, which computer-executable instructions, when executed by the node's processor, perform the discussed process. It is also understood that any transmitting and receiving processes illustrated in the figures may be performed by the node's communication circuitry under the control of the node's processor and the computer-executable instructions (e.g., software) it executes.

[0182] The various techniques described herein may be implemented in connection with hardware or software, or a combination of both, where appropriate. Accordingly, implementations and apparatuses of the subject matter described herein, or certain aspects or portions thereof, may take the form of program code (e.g., instructions) embodied in tangible media, including any other machine-readable storage medium, which, when loaded and executed by a machine, such as a computer, causes the machine to become an apparatus for performing the subject matter described herein. When program code is stored on a medium, the program code may be stored on one or more media that collectively perform actions; i.e., one or more media together comprise code for performing actions; however, if two or more single media are present, any particular portion of the code need not be stored on any particular medium. In the case of program code execution on a programmable device, the computing device generally includes a processor, a storage medium readable by the processor (including volatile and non-volatile memory and / or storage elements), at least one input device, and at least one output device. One or more programs may implement or utilize the processes described in connection with the subject matter described herein, for example, through the use of APIs, reusable controls, etc. Such programs are preferably implemented in a high-level procedural or object-oriented programming language to communicate with a computer system. However, the programs can be implemented in assembly or machine language, if desired. In either case, the language may be a compiled or interpreted language, and combined with hardware implementations.

[0183] Although example embodiments may refer to utilizing aspects of the subject matter described herein in the environment of one or more standalone computing systems, the subject matter described herein is not so limited, but rather may be implemented in connection with any computing environment, such as a network or distributed computing environment. Furthermore, aspects of the subject matter described herein may be implemented within or across multiple processing chips or devices, and storage may be similarly affected across multiple devices. Such devices may include personal computers, network servers, handheld devices, supercomputers, or computers integrated into other systems, such as automobiles and airplanes.

[0184] In describing preferred embodiments of the subject matter of the present disclosure, as illustrated in the Figures, specific terminology will be employed for clarity, however, it is understood that the claimed subject matter is not intended to be limited to the specific terminology so selected, and that each specific element includes all technical equivalents that operate in a similar manner to accomplish a similar purpose.

Claims

1. 1. A wireless transmit / receive unit (WTRU), comprising: a processor, the processor comprising: receiving an indication to change to a non-terrestrial network (NTN) cell from a first terrestrial network (TN) cell, the first TN cell being associated with a first radio access network (RAN)-based notification area (RNA); performing cell reselection to the NTN cell based on the indicator; determining that a cell reselection condition associated with the second TN cell, the second TN cell being associated with the second RNA, is satisfied; a wireless transmit / receive unit (WTRU) configured to perform cell reselection to the second TN cell associated with the second RNA based on the determination that the cell reselection condition is satisfied.

2. The processor: receiving an indication to change the state of the WTRU from an RRC_CONNECTED state to an RRC_INACTIVE state; initiate the change of the state of the WTRU from the RRC_CONNECTED state to the RRC_INACTIVE state; The WTRU of claim 1 , further configured to receive a paging message from the NTN cell during a time period associated with the WTRU being configured to operate in the RRC_INACTIVE state.

3. The processor: During a time period associated with the WTRU being configured to monitor the paging message from the NTN cell, evaluating the second TN cell associated with the second RNA, the evaluation including measuring the second TN cell and determining that the cell reselection condition associated with the second TN cell is satisfied; Initiating a change of the state of the WTRU from the RRC_INACTIVE state to the RRC_CONNECTED state based on the reception of the paging message; The WTRU of claim 2 , further configured to receive a data transmission from the second TN cell during a time period associated with the WTRU being configured to operate in the RRC_CONNECTED state.

4. The processor: performing measurements associated with the NTN cell; 3. The WTRU of claim 2, further configured to send a request for cell reselection to the NTN cell based on the measurements associated with the NTN cell before the change of the state of the WTRU from the RRC_CONNECTED state to the RRC_INACTIVE state, and the indication to change from the first TN cell to the NTN cell is received after the request is sent.

5. The processor: receiving identification information associated with a plurality of TN cells, including the first TN cell associated with the first RNA and the second TN cell associated with the second RNA; monitoring the paging message from the NTN cell; 3. The WTRU of claim 2, further configured to: based on the identification information, perform an evaluation of the plurality of TN cells, the evaluation being limited to the plurality of TN cells, during a time period associated with the WTRU being configured to monitor the paging messages from the NTN cells.

6. The processor: receiving a cell reselection threshold in a radio resource control (RRC) message; 2. The WTRU of claim 1, further configured to: determine a reference signal received power (RSRP) associated with the second TN cell associated with the second RNA, wherein the determination of the satisfaction of the cell reselection condition associated with the second TN cell includes determining that the RSRP associated with the second TN cell is greater than or equal to the cell reselection threshold.

7. The processor: receiving cell reselection priority information in a radio resource control (RRC) message; 2. The WTRU of claim 1, further configured to: determine a cell reselection priority associated with the second TN cell associated with the second RNA, wherein the determination of the satisfaction of the cell reselection condition associated with the second TN cell is based on the cell reselection priority associated with the second TN cell and the cell reselection priority information received in the RRC message.

8. The processor: transmitting to said NTN cell an indication of the change from said first RNA to said second RNA; receiving an indication from the NTN cell to change the state of the WTRU from an RRC_INACTIVE state to an RRC_IDLE state; 2. The WTRU of claim 1, further configured to initiate a change of the state of the WTRU from the RRC_INACTIVE state to the RRC_IDLE state before the cell reselection to the second TN cell is performed based on the indicator.

9. 1. A method implemented by a wireless transmit / receive unit (WTRU), comprising: receiving an indication to change from a first Terrestrial Network (TN) cell, the first TN cell being associated with a first Radio Access Network (RAN)-based Notification Area (RNA), to a Non-Terrestrial Network (NTN) cell; performing cell reselection to the NTN cell based on the indicator; determining that a cell reselection condition associated with a second TN cell, the second TN cell associated with the second RNA, is satisfied; performing cell reselection to the second TN cell associated with the second RNA based on the determination that the cell reselection condition is satisfied.

10. receiving an indication to change the state of the WTRU from an RRC_CONNECTED state to an RRC_INACTIVE state; initiating the change of the state of the WTRU from the RRC_CONNECTED state to the RRC_INACTIVE state; 10. The method of claim 9, further comprising: receiving a paging message from the NTN cell during a time period associated with the WTRU being configured to operate in the RRC_INACTIVE state.

11. evaluating the second TN cell associated with the second RNA during a time period associated with the WTRU being configured to monitor the paging message from the NTN cell, the evaluation including measuring the second TN cell and determining that the cell reselection condition associated with the second TN cell is satisfied; initiating a change of the state of the WTRU from the RRC_INACTIVE state to the RRC_CONNECTED state based on the reception of the paging message; 11. The method of claim 10, further comprising: receiving a data transmission from the second TN cell during a time period associated with the WTRU being configured to operate in the RRC_CONNECTED state.

12. performing measurements associated with the NTN cell; 11. The method of claim 10, further comprising: sending a request for cell reselection to the NTN cell based on the measurements associated with the NTN cell before the change of the state of the WTRU from the RRC_CONNECTED state to the RRC_INACTIVE state, wherein the indication to change from the first TN cell to the NTN cell is received after the request is sent.

13. receiving identification information associated with a plurality of TN cells, including the first TN cell associated with the first RNA and the second TN cell associated with the second RNA; monitoring the paging message from the NTN cell; 10. The method of claim 9, further comprising: performing an evaluation of the plurality of TN cells, the evaluation being limited to the plurality of TN cells, during a time period associated with the WTRU being configured to monitor the paging messages from the NTN cell based on the identification information.

14. receiving a cell reselection threshold in a radio resource control (RRC) message; and determining a reference signal received power (RSRP) associated with the second TN cell associated with the second RNA, wherein the determination of the satisfaction of the cell reselection condition associated with the second TN cell comprises determining that the RSRP associated with the second TN cell is greater than or equal to the cell reselection threshold.

15. receiving cell reselection priority information in a radio resource control (RRC) message; determining a cell reselection priority associated with the second TN cell associated with the second RNA, wherein the determination of the satisfaction of the cell reselection condition associated with the second TN cell is based on the cell reselection priority associated with the second TN cell and the cell reselection priority information received in the RRC message.

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